Microglia and Parkinson

1. Arimoto T, Bing G (2003) Up-regulation of inducible nitric oxide synthase in the substantia nigra by lipopolysaccharide causes Microglial activation and neurodegeneration. Neurobiol.Dis. 12:35-45
   Abstract: The present study was designed to examine whether expression of iNOS was involved in LPS-induced neurodegeneration in rat substantia nigra (SN) and to study the role of NO in the loss of the SN dopaminergic neurons. In Western blot analysis, iNOS was induced in the SN after injection of LPS in a time- and dose-dependent manner. Immunofluorescence and immunohistochemical analyses revealed that the iNOS is located in a fully activated Microglia with the characteristic amoeboid morphology. Furthermore, LPS-induced loss of dopaminergic neurons was significantly inhibited by the administration of L-N(G)-nitroarginine, a selective inhibitor of NOS, and the glucocorticoid dexamethasone. These inhibiting agents for iNOS reduced LPS-induced Microglial activation, suggesting that NO has a role in inflammatory-mediated Microglial activation. These results demonstrate that LPS induces the expression of iNOS in activated Microglia in the SN, and that NO and/or its metabolites may play a crucial role in inflammation-mediated degeneration of dopaminergic neurons

2. Asanuma M, Miyazaki I, Tsuji T, Ogawa N (2003) [New aspects of neuroprotective effects of nonsteroidal anti-inflammatory drugs]. Nihon Shinkei Seishin Yakurigaku Zasshi 23:111-119
   Abstract: Nonsteroidal anti-inflammatory drugs (NSAIDs) exert anti-inflammatory, analgesic and antipyretic activities and are involved in the suppression of prostaglandin synthesis by inhibiting cyclooxygenase (COX), a prostaglandin synthesizing enzyme. It has been recently revealed that NSAIDs also possess inhibitory effects on the generating system of nitric oxide radicals and modulating effects on transcription factors and nuclear receptors which are related to inflammatory reactions. Since it has been reported that inflammatory processes are associated with the pathophysiology of several neurodegenerative diseases and that NSAIDs inhibit amyloid beta-protein-induced neurotoxicity to reduce the risk for Alzheimer's disease, a number of studies have been conducted focusing on the neuroprotective effects of NSAIDs. It has been clarified that the drugs exert neuroprotective effects, which are not related to their COX-inhibiting property, on pathophysiology of various neurological disorders. In this article, new aspects of neuroprotective effects of NSAIDs have been reviewed, especially, in Alzheimer's disease and Parkinson's disease, discussing various pharmacological effects of NSAIDs other than their inhibitory action on COX

3. Beal MF (2003) Mitochondria, oxidative damage, and inflammation in Parkinson's disease. Ann.N.Y.Acad.Sci. 991:120-131
   Abstract: The pathogenesis of Parkinson's disease (PD) remains obscure, but there is increasing evidence that impairment of mitochondrial function, oxidative damage, and inflammation are contributing factors. The present paper reviews the experimental and clinical evidence implicating these processes in PD. There is substantial evidence that there is a deficiency of complex I activity of the mitochondrial electron transport chain in PD. There is also evidence for increased numbers of activated Microglia in both PD postmortem tissue as well as in animal models of PD. Impaired mitochondrial function and activated Microglia may both contribute to oxidative damage in PD. A number of therapies targeting inflammation and mitochondrial dysfunction are efficacious in the MPTP model of PD. Of these, coenzyme Q(10) appears to be particularly promising based on the results of a recent phase 2 clinical trial in which it significantly slowed the progression of PD

4. Cardenas H, Bolin LM (2003) Compromised reactive microgliosis in MPTP-lesioned IL-6 KO mice. Brain Res. 985:89-97
   Abstract: Reactive gliosis, the cellular manifestation of neuroinflammation, is a pathological hallmark of neurodegenerative diseases including Parkinson's disease. The persistent gliosis observed in the Parkinson's disease substantia nigra (SN) and in humans and animals exposed to the neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) may represent a chronic inflammatory response that contributes to pathology. We have previously shown that in the absence of interleukin-6 (IL-6) dopaminergic neurons are more vulnerable to MPTP. Since IL-6 is both an autocrine and paracrine proliferation factor for CNS glia, we investigated reactive gliosis in MPTP-lesioned IL-6 (-/-) mice. While astrogliosis was similar in injured IL-6 (+/+) and IL-6 (-/-) SN pars compacta (pc), microgliosis was severely compromised in IL-6 (-/-) mice. In the absence of IL-6, an acute reactive microgliosis was transient with a complete absence of reactive Microglia at day 7 post-lesion. Extensive reactive microgliosis was observed in the SNpc of MPTP-lesioned IL-6 (+/+) mice. Because glial derived inducible nitric oxide synthase (iNOS) has been implicated in dopaminergic cell death, we examined glial iNOS expression in the IL-6 genotypes to determine if it correlated with the greater vulnerability and reduced microgliosis observed in the MPTP-lesioned IL-6 (-/-) nigrostriatal system. Both reactive Microglia and astrocytes expressed iNOS in the lesioned SNpc. In the IL-6 (-/-) mice, Microglial iNOS expression diminished as reactive microgliosis declined. The data suggest IL-6 regulation of Microglia activation, while iNOS expression appears to be secondary to cell activation

5. Choi SH, Joe EH, Kim SU, Jin BK (2003) Thrombin-induced Microglial activation produces degeneration of nigral dopaminergic neurons in vivo. J.Neurosci. 23:5877-5886
   Abstract: The present study examined whether thrombin-induced Microglial activation could contribute to death of dopaminergic neurons in the rat substantia nigra (SN) in vivo. Seven days after thrombin injection into the SN, tyrosine hydroxylase immunohistochemistry showed a significant loss of nigral dopaminergic neurons. In parallel, thrombin-activated Microglia, visualized by immunohistochemical staining using antibodies against the complement receptor type 3 (OX-42) and the major histocompatibility complex class II antigens were also observed in the SN, where degeneration of nigral neurons was found. Reverse transcription PCR at various time points demonstrated that activated Microglia in vivo exhibited an early and transient expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and several proinflammatory cytokines, including interleukin 1beta (IL-1beta), IL-6, and tumor necrosis factor alpha. Western blot analysis and double-label immunohistochemistry showed an increase in the expression of iNOS and COX-2 and the colocalization of these proteins within Microglia. The thrombin-induced loss of SN dopaminergic neurons was partially inhibited by NG-nitro-L-arginine methyl ester hydrochloride, an NOS inhibitor, and by DuP-697, a COX-2 inhibitor. Additional studies demonstrated that extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) were activated in the SN as early as 30 min after thrombin injection, and that these kinases were localized within Microglia. Inhibition of ERK1/2 and p38 MAPK reduced iNOS and COX-2 mRNA expression and rescued dopaminergic neurons in the SN. The present results strongly suggest that Microglial activation triggered by endogenous compound(s) such as thrombin may be involved in the neuropathological processes of dopaminergic neuronal cell death that occur in Parkinson's disease

6. Collier TJ, Steece-Collier K, McGuire S, Sortwell CE (2003) Cellular models to study dopaminergic injury responses. Ann.N.Y.Acad.Sci. 991:140-151
   Abstract: The study of immature midbrain dopamine (DA) neurons and dopaminergic cell lines in culture provides an opportunity to analyze mechanisms of cell death and avenues of potential intervention relevant to Parkinson's disease (PD) in a controlled environment. Use of cell culture models has provided evidence for different sets of intracellular changes associated with DA neuron death following exposure to the neurotoxins 6-hydroxydopamine and MPP+, supporting roles for oxidative stress and impaired energy metabolism as significant factors endangering these cells. Interference with death of cultured DA neurons has provided an initial test system that has yielded all the identified neurotrophic factors for DA neurons. More recent work suggests that combinations of molecules secreted by myelinating glial cells and their precursors provide even greater neuroprotection for DA neurons. Most recently, culture systems have been used to implicate Microglial activation in DA neuron injury, providing impetus to the investigation of antiinflammatory agents as potential therapeutics for PD. Thus, cell culture models provide an important bidirectional link between mechanistic studies and clinically relevant observations

7. Gao HM, Liu B, Hong JS (2003) Critical role for Microglial NADPH oxidase in rotenone-induced degeneration of dopaminergic neurons. J.Neurosci. 23:6181-6187
   Abstract: Increasing evidence has suggested an important role for environmental toxins such as pesticides in the pathogenesis of Parkinson's disease (PD). Chronic exposure to rotenone, a common herbicide, reproduces features of Parkinsonism in rats. Mechanistically, rotenone-induced dopaminergic neurodegeneration has been associated with both its inhibition of neuronal mitochondrial complex I and the enhancement of activated Microglia. Our previous studies with NADPH oxidase inhibitors, diphenylene iodonium and apocynin, suggested that NADPH oxidase-derived superoxide might be a major factor in mediating the Microglia-enhanced rotenone neurotoxicity. However, because of the relatively low specificity of these inhibitors, the exact source of superoxide induced by rotenone remains to be further determined. In this study, using primary mesencephalic cultures from NADPH oxidase--null (gp91phox-/-) or wild-type (gp91phox+/+) mice, we demonstrated a critical role for Microglial NADPH oxidase in mediating Microglia-enhanced rotenone neurotoxicity. In neuron--glia cultures, dopaminergic neurons from gp91phox-/- mice were more resistant to rotenone neurotoxicity than those from gp91phox+/+ mice. However, in neuron-enriched cultures, the neurotoxicity of rotenone was not different between the two types of mice. More importantly, the addition of Microglia prepared from gp91phox+/+ mice but not from gp91phox-/- mice to neuron-enriched cultures markedly increased rotenone-induced degeneration of dopaminergic neurons. Furthermore, apocynin attenuated rotenone neurotoxicity only in the presence of Microglia from gp91phox+/+ mice. These results indicated that the greatly enhanced neurotoxicity of rotenone was attributed to the release of NADPH oxidase-derived superoxide from activated Microglia. This study also suggested that Microglial NADPH oxidase may be a promising target for PD treatment

8. Gao HM, Hong JS, Zhang W, Liu B (2003) Synergistic dopaminergic neurotoxicity of the pesticide rotenone and inflammogen lipopolysaccharide: relevance to the etiology of Parkinson's disease. J.Neurosci. 23:1228-1236
   Abstract: Parkinson's disease (PD) is characterized by a progressive degeneration of the nigrostriatal dopaminergic pathway resulting in movement disorders. Although its etiology remains unknown, PD may be the final outcome of interactions among multiple factors, including exposure to environmental toxins and the occurrence of inflammation in the brain. In this study, using primary mesencephalic cultures, we observed that nontoxic or minimally toxic concentrations of the pesticide rotenone (0.5 nm) and the inflammogen lipopolysaccharide (LPS) (0.5 ng/ml) synergistically induced dopaminergic neurodegeneration. The synergistic neurotoxicity of rotenone and LPS was observed when the two agents were applied either simultaneously or in tandem. Mechanistically, Microglial NADPH oxidase-mediated generation of reactive oxygen species appeared to be a key contributor to the synergistic dopaminergic neurotoxicity. This conclusion was based on the following observations. First, inhibition of NADPH oxidase or scavenging of free radicals afforded significant neuroprotection. Second, rotenone and LPS synergistically stimulated the NADPH oxidase-mediated release of the superoxide free radical. Third and most importantly, rotenone and LPS failed to induce the synergistic neurotoxicity as well as the production of superoxide in cultures from NADPH oxidase-deficient animals. This is the first demonstration that low concentrations of a pesticide and an inflammogen work in synergy to induce a selective degeneration of dopaminergic neurons. Findings from this study may be highly relevant to the elucidation of the multifactorial etiology of PD and the discovery of effective therapeutic agents for the treatment of the disease

9. Gao HM, Liu B, Zhang W, Hong JS (2003) Synergistic dopaminergic neurotoxicity of MPTP and inflammogen lipopolysaccharide: relevance to the etiology of Parkinson's disease. FASEB J. 17:1957-1959
   Abstract: Parkinson's disease (PD) is a profound movement disorder resulting from progressive degeneration of the nigrostriatal dopaminergic pathway. Although its etiology remains unknown, increasing evidence suggests the involvement of multiple factors such as environmental toxins and genetic susceptibilities in the pathogenesis of PD. In this study using mesencephalic neuron-glia cultures as an in vitro PD model, we demonstrated that the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 0.1-0.5 microM) and an inflammogen lipopolysaccharide (LPS, 0.5 ng/ml) synergistically induced a progressive and selective degeneration of dopaminergic neurons. The synergistic neurotoxicity was observed when both agents were applied either simultaneously or in tandem. The synergistic neurotoxicity was more prominent when lower doses of both agents were applied for a longer period of time. Mechanistically, Microglial NADPH oxidase-mediated generation of reactive oxygen species played a pivotal role in the synergistic neurotoxicity: MPTP and LPS synergistically stimulated the NADPH oxidase-mediated release of superoxide free radical; pharmacological inhibition and genetic inactivation of NADPH oxidase prevented superoxide production and the synergistic neurotoxicity. Additionally, inhibition of nitric oxide synthase afforded significant neuroprotection, suggesting the involvement of nitric oxide in the synergistic neurotoxicity. This study lends strong support for a multifactorial etiology of PD and provides clues for therapeutic interventions

10. Gao HM, Liu B, Zhang W, Hong JS (2003) Novel anti-inflammatory therapy for Parkinson's disease. Trends Pharmacol.Sci. 24:395-401
    Abstract: Parkinson's disease (PD) is a movement disorder that is characterized by progressive degeneration of the nigrostriatal dopamine system. Although dopamine replacement can alleviate symptoms of the disorder, there is no proven therapy to halt the underlying progressive degeneration of dopamine-containing neurons. Recently, increasing evidence from human and animal studies has suggested that neuroinflammation is an important contributor to the neuronal loss in PD. Moreover, the pro-inflammatory agent lipopolysaccharide itself can directly initiate degeneration of dopamine-containing neurons or combine with other environmental factor(s), such as the pesticide rotenone, to exacerbate such neurodegeneration. These effects provide strong support for the involvement of inflammation in the pathogenesis of PD. Furthermore, growing experimental evidence demonstrates that inhibition of the inflammatory response can, in part, prevent degeneration of nigrostriatal dopamine-containing neurons in several animal models of PD, suggesting that inhibition of inflammation might become a promising therapeutic intervention for PD

11. Gao HM, Liu B, Zhang W, Hong JS (2003) Critical role of Microglial NADPH oxidase-derived free radicals in the in vitro MPTP model of Parkinson's disease. FASEB J. 17:1954-1956
    Abstract: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) damages dopaminergic neurons as seen in Parkinson's disease. Although increasing evidence suggests an involvement of glia in MPTP neurotoxicity, the nature of this involvement remains unclear. Exploiting the advantage of cell culture systems, we demonstrated that Microglia, but not astroglia, significantly enhanced the progression of MPTP-induced dopaminergic neurodegeneration. Characterization of the temporal relationship between neurodegeneration and Microglial activation demonstrates that reactive microgliosis resulting from MPTP-initiated neuronal injury, but not direct activation, underlies the Microglia-enhanced MPTP neurotoxicity. Mechanistically, through the release of NADPH oxidase-derived reactive oxygen species, Microglia contribute to the progressive neuronal damage. Among the factors measured, the production of extracellular superoxide was the most prominent. NADPH oxidase inhibitor, apocynin, attenuated MPTP-induced dopaminergic neurodegeneration only in the presence of glia. More importantly, dopaminergic neurons from mice lacking NADPH oxidase, a key enzyme for superoxide production in immune cells, are significantly more resistant to MPTP neurotoxicity than those from wild-type controls, and Microglia dictate the resistance. This study demonstrates that reactive microgliosis triggered by MPTP-induced neuronal injury and NADPH oxidase-mediated superoxide production in Microglia constitute an integral component of MPTP neurotoxicity. This study also suggests that NADPH oxidase may be a promising target for therapeutic interventions in Parkinson's disease

12. Henningson CT, Jr., Stanislaus MA, Gewirtz AM (2003) 28. Embryonic and adult stem cell therapy. J.Allergy Clin.Immunol. 111:S745-S753
    Abstract: Stem cells are characterized by the ability to remain undifferentiated and to self-renew. Embryonic stem cells derived from blastocysts are pluripotent (able to differentiate into many cell types). Adult stem cells, which were traditionally thought to be monopotent multipotent, or tissue restricted, have recently also been shown to have pluripotent properties. Adult bone marrow stem cells have been shown to be capable of differentiating into skeletal muscle, brain Microglia and astroglia, and hepatocytes. Stem cell lines derived from both embryonic stem and embryonic germ cells (from the embryonic gonadal ridge) are pluripotent and capable of self-renewal for long periods. Therefore embryonic stem and germ cells have been widely investigated for their potential to cure diseases by repairing or replacing damaged cells and tissues. Studies in animal models have shown that transplantation of fetal, embryonic stem, or embryonic germ cells may be able to treat some chronic diseases. In this review, we highlight recent developments in the use of stem cells as therapeutic agents for three such diseases: Diabetes, Parkinson disease, and congestive heart failure. We also discuss the potential use of stem cells as gene therapy delivery cells and the scientific and ethical issues that arise with the use of human stem cells

13. Hirsch EC, Breidert T, Rousselet E, Hunot S, Hartmann A, Michel PP (2003) The role of glial reaction and inflammation in Parkinson's disease. Ann.N.Y.Acad.Sci. 991:214-228
    Abstract: The glial reaction is generally considered to be a consequence of neuronal death in neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, and Parkinson's disease. In Parkinson's disease, postmortem examination reveals a loss of dopaminergic neurons in the substantia nigra associated with a massive astrogliosis and the presence of activated Microglial cells. Recent evidence suggests that the disease may progress even when the initial cause of neuronal degeneration has disappeared, suggesting that toxic substances released by the glial cells may be involved in the propagation and perpetuation of neuronal degeneration. Glial cells can release deleterious compounds such as proinflammatory cytokines (TNF-alpha, Il-1beta, IFN-gamma), which may act by stimulating nitric oxide production in glial cells, or which may exert a more direct deleterious effect on dopaminergic neurons by activating receptors that contain intracytoplasmic death domains involved in apoptosis. In line with this possibility, an activation of proteases such as caspase-3 and caspase-8, which are known effectors of apoptosis, has been reported in Parkinson's disease. Yet, caspase inhibitors or invalidation of TNF-alpha receptors does not protect dopaminergic neurons against degeneration in experimental models of the disease, suggesting that manipulation of a single signaling pathway may not be sufficient to protect dopaminergic neurons. In contrast, the antiinflammatory drugs pioglitazone, a PPAR-gamma agonist, and the tetracycline derivative minocycline have been shown to reduce glial activation and protect the substantia nigra in an animal model of the disease. Inhibition of the glial reaction and the inflammatory processes may thus represent a therapeutic target to reduce neuronal degeneration in Parkinson's disease

14. Liu B, Gao HM, Hong JS (2003) Parkinson's disease and exposure to infectious agents and pesticides and the occurrence of brain injuries: role of neuroinflammation. Environ.Health Perspect. 111:1065-1073
    Abstract: Idiopathic Parkinson's disease (PD) is a devastating movement disorder characterized by selective degeneration of the nigrostriatal dopaminergic pathway. Neurodegeneration usually starts in the fifth decade of life and progresses over 5-10 years before reaching the fully symptomatic disease state. Despite decades of intense research, the etiology of sporadic PD and the mechanism underlying the selective neuronal loss remain unknown. However, the late onset and slow-progressing nature of the disease has prompted the consideration of environmental exposure to agrochemicals, including pesticides, as a risk factor. Moreover, increasing evidence suggests that early-life occurrence of inflammation in the brain, as a consequence of either brain injury or exposure to infectious agents, may play a role in the pathogenesis of PD. Most important, there may be a self-propelling cycle of inflammatory process involving brain immune cells (Microglia and astrocytes) that drives the slow yet progressive neurodegenerative process. Deciphering the molecular and cellular mechanisms governing those intricate interactions would significantly advance our understanding of the etiology and pathogenesis of PD and aid the development of therapeutic strategies for the treatment of the disease

15. Liu B, Hong JS (2003) Role of Microglia in inflammation-mediated neurodegenerative diseases: mechanisms and strategies for therapeutic intervention. J.Pharmacol.Exp.Ther. 304:1-7
    Abstract: Evidence from postmortem analysis implicates the involvement of Microglia in the neurodegenerative process of several degenerative neurological diseases, including Alzheimer's disease and Parkinson's disease. It remains to be determined, however, whether Microglial activation plays a role in the initiation stage of disease progression or occurs merely as a response to neuronal death. Activated Microglia secrete a variety of proinflammatory and neurotoxic factors that are believed to induce and/or exacerbate neurodegeneration. In this article, we summarize recent advances on the study of the role of Microglia based on findings from animal and cell culture models in the pathogenesis of neurodegenerative diseases, with particular emphasis on Parkinson's disease. In addition, we also discuss novel approaches to potential therapeutic strategies

16. Muramatsu Y, Kurosaki R, Watanabe H, Michimata M, Matsubara M, Imai Y, Araki T (2003) Expression of S-100 protein is related to neuronal damage in MPTP-treated mice. Glia 42:307-313
    Abstract: S-100beta is a calcium-binding protein expressed at high levels in brain and is known as a marker of brain damage. However, little is known about the role of S-100beta protein during neuronal damage caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). To determine whether S-100beta protein is induced in glial cells after MPTP treatment, we investigated the expression of S-100 protein immunohistochemically, using MPTP-treated mice. We also examined the change of neurons and glial cells in mice after MPTP treatment. The present study shows that tyrosine hydroxylase (TH) immunoreactivity decreased gradually in the striatum and substantia nigra from 1 day after MPTP treatment. Thereafter, TH-immunopositive cells and fibers decreased in the striatum and substantia nigra at 3 days after MPTP treatment. In contrast, S-100-immunopositive cells and glial fibrillary acidic protein (GFAP)-immunopositive cells increased markedly in the striatum and substantia nigra at 3 days after MPTP treatment. Seven days after MPTP treatment, S-100-immunopositive cells decreased in the striatum and substantia nigra. However, the number of GFAP-immunopositive cells increased in these regions. In double-labeled immunostaining with anti-S-100 and anti-GFAP antibodies, S-100 immunoreactivity was observed only in the GFAP-positive astrocytes. These results provide evidence that astrocytic activation may play a role in the pathogenesis of MPTP-induced degeneration of dopaminergic neurons. Furthermore, the present study demonstrates that S-100 protein is expressed selectively by astrocytes, but not by Microglia, after MPTP treatment. These results provide valuable information for the pathogenesis of the acute stage of Parkinson's disease

17. Piao YS, Mori F, Hayashi S, Tanji K, Yoshimoto M, Kakita A, Wakabayashi K, Takahashi H (2003) Alpha-synuclein pathology affecting Bergmann glia of the cerebellum in patients with alpha-synucleinopathies. Acta Neuropathol.(Berl) 105:403-409
    Abstract: We carried out immunohistochemical examinations of the brains (cerebella) of patients who had suffered from Parkinson's disease (PD), diffuse Lewy body disease (DLBD) or multiple system atrophy (MSA), using antibodies specific for alpha-synuclein. Alpha-synuclein-positive doughnut-shaped structures were found occasionally in the cerebellar molecular layer in some of these patients. Double-labeling immunofluorescence and immunoelectron microscopy studies revealed that these alpha-synuclein-positive doughnut-shaped structures were located in the glial fibrillary acidic protein-positive radial processes of Bergmann glia, corresponding to the outer area of Lewy body-like inclusions, and consisted of granulo-filamentous structures. These findings indicate that, although not frequently, Bergmann glia of the cerebellum are also the targets of alpha-synuclein pathology in alpha-synucleinopathies such as PD, DLBD and MSA

18. Riess O, Berg D, Kruger R, Schulz JB (2003) Therapeutic strategies for Parkinson's disease based on data derived from genetic research. J.Neurol. 250 Suppl 1:I3-10
    Abstract: Following the identification of mutations in alpha-synuclein as the cause of some rare forms of familial Parkinson's disease (PD), genetic research has uncovered numerous gene loci of PD. Meanwhile, several neurodegenerative diseases have been shown to accumulate a-synuclein in neuronal and glial cells summarizing this group of diseases as synucleinopathies. All currently known gene defects causing PD alter the ubiquitin-proteasomal pathway of protein degradation. Identification of these disease mutations allows studying the functional consequences which lead to cellular dysfunction and cell death in cell culture and transgenic animal models, to identify therapeutic targets and to test potential protective strategies in these models

19. Saura J, Pares M, Bove J, Pezzi S, Alberch J, Marin C, Tolosa E, Marti MJ (2003) Intranigral infusion of interleukin-1beta activates astrocytes and protects from subsequent 6-hydroxydopamine neurotoxicity. J.Neurochem. 85:651-661
    Abstract: Activation of glial cells is a prevalent response to neuronal damage in brain disease and ageing, with potential neuroprotective and neurotoxic consequences. We were interested in studying the role of glial activation on dopaminergic neurons of the substantia nigra in an animal model of Parkinson's disease. Thus, we evaluated the effect of a pre-existing glial activation on the dopaminergic neuronal death induced by striatal infusion of 6-hydroxydopamine. We established a model of local glial activation by stereotaxic infusion of interleukin-1beta in the substantia nigra of adult rats. Interleukin-1beta (20 ng) induced a marked activation of astrocytes at days 2, 5 and 10, revealed by heat-shock protein 27 and glial fibrillary acid protein immunohistochemistry, but did not affect the Microglial markers OX-42 and heat-shock proteins 32 or 47. Intranigral infusion of interleukin-1beta 5 days before a striatal injection of 6-hydroxydopamine significantly protected nigral dopaminergic cell bodies, but not striatal terminals from the 6-hydroxydopamine lesion. Also, in the animals pre-treated with interleukin-1beta, a significant prevention of 6-hydroxydopamine-induced reduction of adjusting steps, but not of 6-hydroxydopamine-induced amphetamine rotations, were observed. These data show the characterization of a novel model of local astroglial activation in the substantia nigra and support the hypothesis of a neuroprotective role of activated astrocytes in Parkinson's disease

20. Sherer TB, Betarbet R, Kim JH, Greenamyre JT (2003) Selective Microglial activation in the rat rotenone model of Parkinson's disease. Neurosci.Lett. 341:87-90
    Abstract: Chronic rotenone exposure reproduces features of Parkinson's disease (PD) (Nat. Neurosci. 3 (2000) 1301; Exp. Neurol. 179 (2003) 9). We investigated the role of glial activation in rotenone toxicity in vivo. Male Lewis rats received 2-3 mg/kg rotenone per day for up to 4 weeks. In 50% of surviving rotenone-treated animals, there was nigrostriatal dopaminergic degeneration, marked by reduced tyrosine hydroxylase immunoreactivity). Extensive Microglial activation, determined by OX-42-ir, occurred in striatum and nigra of rotenone-treated animals, and was prominent before anatomical evidence of dopaminergic lesions. Microglia enlarged and developed short, stubby processes in rotenone-treated animals. Rotenone-induced Microglial activation was less pronounced in cortex. Reactive astrocytosis was minimal and limited to a thin rim around the lesion. Marked Microglial activation with minimal astrocytosis is another pathological feature of PD reproduced by rotenone treatment

21. Sugama S, Yang L, Cho BP, DeGiorgio LA, Lorenzl S, Albers DS, Beal MF, Volpe BT, Joh TH (2003) Age-related Microglial activation in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurodegeneration in C57BL/6 mice. Brain Res. 964:288-294
    Abstract: Microglial activation was investigated in the brains of young (3 months old) and older (9-12 months old) mice following administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Tyrosine hydroxylase (TH)-positive neuronal loss differed significantly between young and older mice. Importantly, the two groups clearly demonstrated a distinct Microglial activation pattern. In young mice which showed TH neuronal loss at 1 day (33.4%), 3 days (45.1%), 7 days (47.1%) and 14 days (46.9%), Microglial activation was first observed at 1 day, with lesser activation at 3 days and none shown later than 7 days. In contrast, in older mice which showed TH neuronal loss at 1 day (49.6%), 3 days (56.1%), 7 days (71.7%) and 14 days (72.1%), Microglial activation occurred at 1 day, further intensified at 3-7 days, and was largely abated by 14 days. The double immunohistochemistry further demonstrated that the activated Microglia surrounded dopaminergic neurons in older mice at 7 days, which was sharply in contrast to the young mice which were devoid of massive Microglial activation in the SN later than 3 days after MPTP treatment. The present study suggests that age-related Microglial activation in the SN may be relevant to the higher susceptibility to MPTP neurotoxicity in older mice

22. Teismann P, Tieu K, Choi DK, Wu DC, Naini A, Hunot S, Vila M, Jackson-Lewis V, Przedborski S (2003) Cyclooxygenase-2 is instrumental in Parkinson's disease neurodegeneration. Proc.Natl.Acad.Sci.U.S.A 100:5473-5478
    Abstract: Parkinson's disease (PD) is a neurodegenerative disorder of uncertain pathogenesis characterized by the loss of the nigrostriatal dopaminergic neurons, which can be modeled by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Increased expression of cyclooxygenase type 2 (COX-2) and production of prostaglandin E(2) have been implicated in neurodegeneration in several pathological settings. Here we show that COX-2, the rate-limiting enzyme in prostaglandin E(2) synthesis, is up-regulated in brain dopaminergic neurons of both PD and MPTP mice. COX-2 induction occurs through a JNKc-Jun-dependent mechanism after MPTP administration. We demonstrate that targeting COX-2 does not protect against MPTP-induced dopaminergic neurodegeneration by mitigating inflammation. Instead, we provide evidence that COX-2 inhibition prevents the formation of the oxidant species dopamine-quinone, which has been implicated in the pathogenesis of PD. This study supports a critical role for COX-2 in both the pathogenesis and selectivity of the PD neurodegenerative process. Because of the safety record of the COX-2 inhibitors, and their ability to penetrate the blood-brain barrier, these drugs may be therapies for PD

23. Teismann P, Tieu K, Cohen O, Choi DK, Wu dC, Marks D, Vila M, Jackson-Lewis V, Przedborski S (2003) Pathogenic role of glial cells in Parkinson's disease. Mov Disord. 18:121-129
    Abstract: Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons in the substantia nigra pars compacta (SNpc). The loss of these neurons is associated with a glial response composed mainly of activated Microglial cells and, to a lesser extent, of reactive astrocytes. This glial response may be the source of trophic factors and can protect against reactive oxygen species and glutamate. Alternatively, this glial response can also mediate a variety of deleterious events related to the production of pro-oxidant reactive species, and pro-inflammatory prostaglandin and cytokines. We discuss the potential protective and deleterious effects of glial cells in the SNpc of PD and examine how those factors may contribute to the pathogenesis of this disease

24. Wilms H, Rosenstiel P, Sievers J, Deuschl G, Zecca L, Lucius R (2003) Activation of Microglia by human neuromelanin is NF-kappaB dependent and involves p38 mitogen-activated protein kinase: implications for Parkinson's disease. FASEB J. 17:500-502
    Abstract: It has been suggested that Microglial inflammation augments the progression of Parkinson's disease (PD). However, endogenous factors initiating Microglial activation are largely unknown. We therefore investigated the effects of human neuromelanin (NM) on the release of neurotoxic mediators and the underlying signaling pathways from rat Microglia in vitro. The addition of NM to Microglial cultures induced positive chemotactic effects, activated the proinflammatory transcription factor nuclear factor kappaB (NF-kappaB) via phosphorylation and degradation of the inhibitor protein kappaB (IkappaB), and led to an up-regulation of tumor necrosis factor alpha, interleukin-6, and nitric oxide. The impairment of NF-kappaB function by the IkappaB kinase inhibitor sulfasalazine was paralleled by a decline in neurotoxic mediators. NM also activated p38 mitogen-activated protein kinase (MAPK), the inhibition of this pathway by SB203580 diminished phosphorylation of the transactivation domain of the p65 subunit of NF-kappaB. These findings demonstrate a crucial role of NM in the pathogenesis of PD by augmentation of Microglial activation, leading to a vicious cycle of neuronal death, exposure of additional neuromelanin, and chronification of inflammation. The antagonization of Microglial activation by a pharmacological intervention targeting Microglial NF-kappaB or p38 MAPK could point to additional venues in the treatment of PD

25. Wu DC, Teismann P, Tieu K, Vila M, Jackson-Lewis V, Ischiropoulos H, Przedborski S (2003) NADPH oxidase mediates oxidative stress in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. Proc.Natl.Acad.Sci.U.S.A 100:6145-6150
    Abstract: Parkinson's disease (PD) is a neurodegenerative disorder of uncertain pathogenesis characterized by a loss of substantia nigra pars compacta (SNpc) dopaminergic (DA) neurons, and can be modeled by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Both inflammatory processes and oxidative stress may contribute to

26. Wullner U, Klockgether T (2003) Inflammation in Parkinson's disease. J.Neurol. 250 Suppl 1:I35-I38
    Abstract: Several studies of Parkinson's disease (PD) patients and experimental models of PD indicate the presence of an inflammatory process in PD. Although the primary cellular mechanisms remain to be clarified, activation of resident Microglia appears to aggravate or even maintain the disease process in PD. Modulation of inflammatory mechanisms could provide a new neuroprotective therapy in PD

27. Al Sarraj S, Maekawa S, Kibble M, Everall I, Leigh N (2002) Ubiquitin-only intraneuronal inclusion in the substantia nigra is a characteristic feature of motor neurone disease with dementia. Neuropathol.Appl.Neurobiol. 28:120-128
    Abstract: Two types of ubiquitinated inclusions have been described in motor neurone disease (MND). (1) Skein or globular ubiquitinated inclusions in the motor neurones (more frequently in the lower motor neurones). This is a characteristic feature of all motor neurone disease categories. (2) Dot-shape or crescentric ubiquitinated inclusions in the upper layers of cortex and dentate gyrus described in cases of motor neurone disease with dementia (DMND). We investigated the substantia nigra (SN) in MND cases; two cases of motor neurone disease inclusion body (MND-IB) dementia, six cases of DMND, 14 cases of MND (including one case from Guam and two cases of familial SOD1 mutation), four cases of Parkinson's disease (PD), and 10 cases of age-matched normal controls. SN and spinal cord sections were stained with ubiquitin (alpha-synuclein, tau, PGM1, SMI-31 and SOD1 antibodies). The neuronal density in SN was quantified by using a computer-based image analysis system. Four out of six DMND cases showed rounded ubiquitin positive inclusions with irregular frayed edges, associated with neuronal loss, reactive astrocytosis and a large number of activated Microglia cells. These inclusions are negative with antibodies to (alpha-synuclein, tau, SMI-31 and SOD1). The SN in cases from MND-IB dementia and MND showed occasional neuronal loss and no inclusions. The ubiquitin-only inclusions in SN of DMND cases are similar (but not identical) to the ubiquitinated inclusions described previously in the spinal cord of MND cases and are distinct from Lewy bodies (LBs). The degeneration of SN is most likely a primary neurodegenerative process of motor neurone disease type frequently involving the DMND cases. MND disease is a spectrum and multisystem disorder with DMND located at the extreme end of a spectrum affecting the CNS more widely than just the motor system

28. Breidert T, Callebert J, Heneka MT, Landreth G, Launay JM, Hirsch EC (2002) Protective action of the peroxisome proliferator-activated receptor-gamma agonist pioglitazone in a mouse model of Parkinson's disease. J.Neurochem. 82:615-624
    Abstract: We examined the effect of pioglitazone, a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist of the thiazolidinedione class, on dopaminergic nerve cell death and glial activation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. The acute intoxication of C57BL/6 mice with MPTP led to nigrostriatal injury, as determined by tyrosine hydroxylase (TH) immunocytochemistry, and HPLC detection of striatal dopamine and metabolites. Damage to the nigrostriatal dopamine system was accompanied by a transient activation of Microglia, as determined by macrophage antigen-1 (Mac-1) and inducible nitric oxide synthase (iNOS) immunoreactivity, and a prolonged astrocytic response. Orally administered pioglitazone (approximately 20 mg/kg/day) attenuated the MPTP-induced glial activation and prevented the dopaminergic cell loss in the substantia nigra pars compacta (SNpc). In contrast, there was little reduction of MPTP-induced dopamine depletion, with no detectable effect on loss of TH immunoreactivity and glial response in the striatum of pioglitazone-treated animals. Low levels of PPARgamma expression were detected in the ventral mesencephalon and striatum, and were unaffected by MPTP or pioglitazone treatment. Since pioglitazone affects primarily the SNpc in our model, different PPARgamma-independent mechanisms may regulate glial activation in the dopaminergic terminals compared with the dopaminergic cell bodies after acute MPTP intoxication

29. Castano A, Herrera AJ, Cano J, Machado A (2002) The degenerative effect of a single intranigral injection of LPS on the dopaminergic system is prevented by dexamethasone, and not mimicked by rh-TNF-alpha, IL-1beta and IFN-gamma. J.Neurochem. 81:150-157
    Abstract: It is becoming widely accepted that the inflammatory response is involved in neurodegenerative disease. In this context, we have developed an animal model of dopaminergic system degeneration by the intranigral injection of lipopolysaccharide (LPS), a potent inductor of inflammation. To address the importance of the inflammatory response in the LPS-induced degeneration of nigral dopaminergic neurones, we carried out two different kinds of studies: (i) the possible protective effect of an anti-inflammatory compound, and (ii) the effect of the intranigral injection of inflammatory cytokines (TNF-alpha, IL-1beta and IFN-gamma) on dopaminergic neurones viability. Present results show that dexamethasone, a potent anti-inflammatory drug that interferes with many of the features characterizing pro-inflammatory glial activation, prevented the loss of catecholamine content, Tyrosine hydroxylase (TH) activity and TH immunostaining induced by LPS-injection and also the bulk activation of Microglia/macrophages. Surprisingly, injection of the pro-inflammatory cytokines failed to reproduce the LPS effect. Taken together, our results suggest that inflammatory response is implicated in LPS-induced neurodegeneration. This damage may be due, at least in part, to a cascade of events independent of that described for TNF-alpha/IL-1 beta/IFN-gamma

30. Cicchetti F, Brownell AL, Williams K, Chen YI, Livni E, Isacson O (2002) Neuroinflammation of the nigrostriatal pathway during progressive 6-OHDA dopamine degeneration in rats monitored by immunohistochemistry and PET imaging. Eur.J.Neurosci. 15:991-998
    Abstract: We investigated the Microglial response to progressive dopamine neuron degeneration using in vivo positron emission tomography (PET) imaging and postmortem analyses in a Parkinson's disease (PD) rat model induced by unilateral (right side) intrastriatal administration of 6-hydroxydopamine (6-OHDA). Degeneration of the dopamine system was monitored by PET imaging of presynaptic dopamine transporters using a specific ligand (11)C-CFT (2beta-carbomethoxy-3beta-(4-fluorophenyl) tropane). Binding of (11)C-CFT was markedly reduced in the striatum indicating dopaminergic degeneration. Parallel PET studies of (11)C-PK11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3 isoquinoline carboxamide) (specific ligand for activated Microglia) showed increased binding in the striatum and substantia nigra indicative of a Microglial response. Postmortem immunohistochemical analyses were performed with antibodies against CR3 for Microglia/macrophage activation. Using a qualitative postmortem index for Microglial activation we found an initially focal, then widespread Microglial response at striatal and nigral levels at 4 weeks postlesion. These data support the hypothesis that inflammation is a significant component of progressive dopaminergic degeneration that can be monitored by PET imaging

31. Czlonkowska A, Kurkowska-Jastrzebska I, Czlonkowski A, Peter D, Stefano GB (2002) Immune processes in the pathogenesis of Parkinson's disease - a potential role for Microglia and nitric oxide. Med.Sci.Monit. 8:RA165-RA177
    Abstract: It has been known for many years that immune system alterations occur in Parkinson's disease (PD). Changes in lymphocyte populations in cerebrospinal fluid and blood, immunoglobulin synthesis, and cytokine and acute phase protein production have been observed in patients with PD. In this regard, PD patients exhibit a lower frequency of infections and cancer, suggesting that immune system stimulation may occur. This hypothesis is further supported by the observation of T-cell activation leading to the production of interferon gamma in PD. As in other CNS degenerative diseases, in damaged regions in the brains of PD patients, there is evidence of inflammation, characterized by glial reaction (especially Microglia), as well as increased expression of HLA-DR antigens, cytokines, and components of complement. These observations suggest that immune system mechanisms are involved in the pathogenesis of neuronal damage in PD. The cellular mechanisms of primary injury in PD have not been clarified, however, but it is likely that mitochondrial mutations, oxidative stress and apoptosis play a role. Furthermore, inflammation initiated by neuronal damage in the striatum and the substantia nigra in PD may aggravate the course of the disease. These observations suggest that treatment with anti-inflammatory drugs may act to slow progression of PD

32. Gao HM, Hong JS, Zhang W, Liu B (2002) Distinct role for Microglia in rotenone-induced degeneration of dopaminergic neurons. J.Neurosci. 22:782-790
    Abstract: Increasing evidence has suggested an important role for environmental factors such as exposure to pesticides in the pathogenesis of Parkinson's disease. In experimental animals the exposure to a common herbicide, rotenone, induces features of Parkinsonism; mechanistically, rotenone-induced destruction of dopaminergic neurons has been attributed to its inhibition of the activity of neuronal mitochondrial complex I. However, the role of Microglia, the resident brain immune cells in rotenone-induced neurodegeneration, has not been reported. Using primary neuron-enriched and neuron/glia cultures from the rat mesencephalon, we discovered an extraordinary feature for rotenone-induced degeneration of cultured dopaminergic neurons. Although little neurotoxicity was detected in neuron-enriched cultures after treatment for 8 d with up to 20 nm rotenone, significant and selective dopaminergic neurodegeneration was observed in neuron/glia cultures 2 d after treatment with 20 nm rotenone or 8 d after treatment with 1 nm rotenone. The greatly enhanced neurodegenerative ability of rotenone was attributed to the presence of glia, especially Microglia, because the addition of Microglia to neuron-enriched cultures markedly increased their susceptibility to rotenone. Mechanistically, rotenone stimulated the release of superoxide from Microglia that was attenuated by inhibitors of NADPH oxidase. Furthermore, inhibition of NADPH oxidase or scavenging of superoxide significantly reduced the rotenone-induced neurotoxicity. This is the first report demonstrating that Microglia play a pivotal role in rotenone-induced degeneration of dopaminergic neurons. The results of this study should advance our understanding of the mechanism of action for pesticides in the pathogenesis of Parkinson's disease

33. Gao HM, Jiang J, Wilson B, Zhang W, Hong JS, Liu B (2002) Microglial activation-mediated delayed and progressive degeneration of rat nigral dopaminergic neurons: relevance to Parkinson's disease. J.Neurochem. 81:1285-1297
    Abstract: The etiology of sporadic Parkinson's disease (PD) remains unknown. Increasing evidence has suggested a role for inflammation in the brain in the pathogenesis of PD. However, it has not been clearly demonstrated whether Microglial activation, the most integral part of the brain inflammatory process, will result in a delayed and progressive degeneration of dopaminergic neurons in substantia nigra, a hallmark of PD. We report here that chronic infusion of an inflammagen lipopolysaccharide at 5 ng/h for 2 weeks into rat brain triggered a rapid activation of Microglia that reached a plateau in 2 weeks, followed by a delayed and gradual loss of nigral dopaminergic neurons that began at between 4 and 6 weeks and reached 70% by 10 weeks. Further investigation of the underlying mechanism of action of Microglia-mediated neurotoxicity using rat mesencephalic neuron-glia cultures demonstrated that low concentrations of lipopolysaccharide (0.1-10 ng/mL)-induced Microglial activation and production of neurotoxic factors preceded the progressive and selective degeneration of dopaminergic neurons. Among the factors produced by activated Microglia, the NADPH oxidase-mediated release of superoxide appeared to be a predominant effector of neurodegeneration, consistent with the notion that dopaminergic neurons are particularly vulnerable to oxidative insults. This is the first report that Microglial activation induced by chronic exposure to inflammagen was capable of inducing a delayed and selective degeneration of nigral dopaminergic neurons and that Microglia-originated free radicals play a pivotal role in dopaminergic neurotoxicity in this inflammation-mediated model of PD

34. He Y, Le WD, Appel SH (2002) Role of Fcgamma receptors in nigral cell injury induced by Parkinson disease immunoglobulin injection into mouse substantia nigra. Exp.Neurol. 176:322-327
    Abstract: Immune/inflammatory factors have been implicated in the pathogenesis of Parkinson's disease (PD). Immunoglobulin G (IgG) from patients with PD can induce injury of dopaminergic neurons following stereotaxic injection into rat substantia nigra (SN). The PD IgG can be demonstrated in vitro to activate Microglia via the Fcgamma receptor (Fcgamma R) and induce dopaminergic cell injury. To confirm the involvement of Microglia and their Fcgamma R in IgG-induced lesions of SN in vivo we analyzed the tyrosine hydroxylase (TH)-positive cell loss in SN par compacta (SNpc) in mice lacking Fcgamma receptors (Fcgamma R(-/-)) and wild type (Fcgamma R(+/+)). At 1 day after stereotaxic injection of PD IgG into the SN of Fcgamma R(+/+) mice there was a 27% increase in the number of CD11b-positive Microglial cells and no significant loss of TH-positive cells. At 14 days after the stereotaxic injection, the number of Microglial cells was increased by 42%, accompanied by a 40% loss of TH-positive neurons in the SNpc. PD IgG injection in Fcgamma R(-/-) mice resulted in no significant increase of Microglia and no loss of TH-positive cells in the SNpc at any time point. The injection of F(ab')(2) fragments of PD IgG was able to induce TH-positive neuronal loss in the SNpc only when the injected animals raised antibodies against the injected human IgG fragments, which confirmed the importance of the Fcgamma R in Microglial activation and nigral injury

35. Iravani MM, Kashefi K, Mander P, Rose S, Jenner P (2002) Involvement of inducible nitric oxide synthase in inflammation-induced dopaminergic neurodegeneration. Neuroscience 110:49-58
    Abstract: The loss of dopaminergic neurones in the substantia nigra with Parkinson's disease may result from inflammation-induced proliferation of Microglia and reactive macrophages expressing inducible nitric oxide synthase (iNOS). We have investigated the effects of the supranigral administration of lipopolysaccharide on iNOS-immunoreactivity, 3-nitrotyrosine formation and tyrosine hydroxylase-immunoreactive neuronal number, and retrogradely labelled fluorogold-positive neurones in the ventral mesencephalon in male Wistar rats. Following supranigral lipopolysaccharide injection, 16-18 h previously, there was intense expression of NADPH-diaphorase and iNOS-immunoreactivity in non-neuronal, macrophage-like cells. This was accompanied by intense expression of glial fibrillary acidic protein-immunoreactive astrocytosis in the substantia nigra. There were also significant reductions in the number of tyrosine hydroxylase(50-60%)- and fluorogold (65-75%)-positive neurones in the substantia nigra. In contrast, tyrosine hydroxylase-immunoreactivity in the ventral tegmental area was not altered. Pre-treatment of animals with the iNOS inhibitor, S-methylisothiourea (10 mg kg(-1), i.p.), led to a significant reduction of lipopolysaccharide-induced cell death. Similar reduction of tyrosine hydroxylase-immunoreactivity and fluorogold-labelled neurones in the substantia nigra following lipopolysaccharide administration suggests dopaminergic cell death rather than down-regulation of tyrosine hydroxylase. We conclude that the expression of iNOS- and 3-nitrotyrosine-immunoreactivity and reduction of cell death by S-methylisothiourea suggest the effects of lipopolysaccharide may be nitric oxide-mediated, although other actions of lipopolysaccharide (independent of iNOS induction) cannot be ruled out

36. Koutsilieri E, Scheller C, Grunblatt E, Nara K, Li J, Riederer P (2002) Free radicals in Parkinson's disease. J.Neurol. 249 Suppl 2:II1-II5
    Abstract: Although there are a number of hypotheses to explain the pathobiochemistry of Parkinson's disease (PD), the one on oxidative stress (OS) has gained major interest. The evidence for OS participation as a cause of PD can be summarized as follows: 1) OS is involved in physiological aging, 2) there is ample evidence that OS is significantly enhanced in PD compared to age-matched healthy persons, 3) OS is an early feature of PD because OS-dependent aggregation of proteins in the form of advanced glycation end products can be imaged in Lewy bodies at a time in a person's life, when no phenotype of a neurodegenerative disorder is evident, 4) Experimental models of PD show OS and degeneration of dopaminergic neurons. The toxin-induced neurodegeneration can be blocked by antioxidants, and 5) Activated Microglia, known to release free radicals and inflammatory cytokines, are present in brains of Parkinsonian patients.In conclusion, a great body of evidence points to the view that OS is a major component underlying the pathobiochemistry of PD. Together a genetic disposition and endogenous/exogenous toxic events of various origins result in a synergistic cascade of toxicity which leads to dysfunction and finally to cell death of dopaminergic neurons. Again, OS plays a significant role in generating cell death signals including apoptosis

37. Koutsilieri E, Scheller C, Tribl F, Riederer P (2002) Degeneration of neuronal cells due to oxidative stress--Microglial contribution. Parkinsonism.Relat Disord. 8:401-406
    Abstract: Various neurodegenerative disorders including Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis have been causally linked to the generation of free radicals and oxidative stress. In this review, we discuss the implication of oxidative stress in neuronal death and point out the role of intracellular signaling pathways leading to activation of transcription factors associated with cell death and repair. In particular, the impact of Microglia as contributors in promoting oxidative stress in neurodegeneration is highlighted. Finally, pivotal molecular targets for drug therapies of brain disorders are reported

38. Kramer BC, Yabut JA, Cheong J, JnoBaptiste R, Robakis T, Olanow CW, Mytilineou C (2002) Lipopolysaccharide prevents cell death caused by glutathione depletion: possible mechanisms of protection. Neuroscience 114:361-372
    Abstract: Glutathione is an important cellular antioxidant present at high concentrations in the brain. We have previously demonstrated that depletion of glutathione in mesencephalic cultures results in cell death and that the presence of glia is necessary for the expression of toxicity. Cell death following glutathione depletion can be prevented by inhibition of lipoxygenase activity, implicating arachidonic acid metabolism in the toxic events. In this study we examined the effect of glial activation, known to cause secretion of cytokines and release of arachidonic acid, on the toxicity induced by glutathione depletion. Our data show that treatment with the endotoxin lipopolysaccharide activated glial cells in mesencephalic cultures, increased interleukin-1beta in Microglia and caused depletion of glutathione. The overall effect of lipopolysaccharide treatment, however, was protection from damage caused by glutathione depletion. Addition of cytokines or growth factors, normally secreted by activated glia, did not modify L-buthionine sulfoximine toxicity, although basic fibroblast growth factor provided some protection. A large increase in the protein content and the activity of Mn-superoxide dismutase, observed after lipopolysaccharide treatment, may indicate a role for this mitochondrial antioxidant enzyme in the protective effect of lipopolysaccharide. This was supported by the suppression of toxicity by exogenous superoxide dismutase. Our data suggest that superoxide contributes to the damage caused by glutathione depletion and that up-regulation of superoxide dismutase may offer protection in neurodegenerative diseases associated with glutathione depletion and oxidative stress

39. Kurkowska-Jastrzebska I, Babiuch M, Joniec I, Przybylkowski A, Czlonkowski A, Czlonkowska A (2002) Indomethacin protects against neurodegeneration caused by MPTP intoxication in mice. Int.Immunopharmacol. 2:1213-1218
    Abstract: The anti-inflammatory agents are postulated to be effective in treating neurodegenerative disorders. In this study, we showed that indomethacin (IND) in the dose of 1 mg/kg protected neurons against toxic damage caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice model of Parkinson's disease. IND also diminished Microglial activation and lymphocytic infiltration in the injured areas. These observations suggest that anti-inflammatory properties of IND may play a role in the neuron's protection in this model. However, diminished inflammatory reaction may be secondary to less neuronal damage

40. Lee YB, Nagai A, Kim SU (2002) Cytokines, chemokines, and cytokine receptors in human Microglia. J.Neurosci.Res. 69:94-103
    Abstract: Enriched populations of human Microglial cells were isolated from mixed cell cultures prepared from embryonic human telencephalon tissues. Human Microglial cells exhibited cell type-specific antigens for macrophage-Microglia lineage cells including CD11b (Mac-1), CD68, B7-2 (CD86), HLA-ABC, HLA-DR and ricinus communis aggulutinin lectin-1 (RCA-1), and actively phagocytosed latex beads. Gene expression and protein production of cytokines, chemokines and cytokine/chemokine receptors were investigated in the purified populations of human Microglia. Normal unstimulated human Microglia expressed constitutively mRNA transcripts for interleukin- 1beta (IL-1beta) -6, -8, -10, -12, -15, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and monocyte chemoattractant protein-1 (MCP-1), while treatment with lipopolysaccharide (LPS) or amyloid beta peptides (Abeta) led to increased expression of mRNA levels of IL-8, IL-10, IL-12, TNF-alpha, MIP-1alpha, MIP-1beta, and MCP-1. Human Microglia, in addition, expressed mRNA transcripts for IL-1RI, IL-1RII, IL-5R, IL-6R, IL-8R, IL-9R, IL-10R, IL-12R, IL-13R, and IL-15R. Enzyme-linked immunosorbent assays (ELISA) showed increased protein levels in culture media of IL-1beta, IL-8, TNF-alpha, and MIP-1alpha in human Microglia following treatment with LPS or Abeta. Increased TNF-alpha release from human Microglia following LPS treatment was completely inhibited with IL-10 pretreatment, but not with IL-6, IL-9, IL-12, IL-13, or transforming growth factor-beta (TGF-beta). Present results should help in understanding the basic Microglial biology, but also the pathophysiology of activated Microglia in neurological diseases such as Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, stroke, and neurotrauma

41. Lorenzl S, Albers DS, Narr S, Chirichigno J, Beal MF (2002) Expression of MMP-2, MMP-9, and MMP-1 and their endogenous counterregulators TIMP-1 and TIMP-2 in postmortem brain tissue of Parkinson's disease. Exp.Neurol. 178:13-20
    Abstract: We investigated the levels and tissue localization of matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9) in postmortem brain tissue from Parkinson's disease (PD) and age-matched control cases. Using zymography, we found reduced MMP-2 levels in PD cases in the substantia nigra as compared to controls; levels of MMP-2 were not significantly changed in the cortex and the hippocampus. MMP-9 levels were unchanged in the investigated brain regions. Immunohistochemically, MMP-2 was localized primarily in astrocytes and Microglia cells, whereas MMP-9 was predominantly neuronal. Levels of TIMP-1, an endogenous tissue inhibitor of MMPs, were significantly elevated in the substantia nigra, but not in the cortex and hippocampus. TIMP-2 levels were unchanged in PD. To investigate whether increased TIMP-1 levels in the substantia nigra might be due to increased MMP-1 expression, we measured MMP-1 levels using Western blots. MMP-1 levels were unchanged in PD cases compared to controls. Together, these data show alterations of MMP-2 and TIMP-1 in the substantia nigra of PD, consistent with the possibility that alterations in MMPs/TIMPs may contribute to disease pathogenesis

42. McGeer PL, Yasojima K, McGeer EG (2002) Association of interleukin-1 beta polymorphisms with idiopathic Parkinson's disease. Neurosci.Lett. 326:67-69
    Abstract: Activated Microglia surround degenerating substantia nigra neurons in Parkinson's disease (PD). Such Microglia produce high levels of interleukin-1 beta (IL-1 beta) and interleukin-1 alpha (IL-1 alpha). T and C alleles exist for the IL-1 beta-511 regulatory region as well as for the IL-1 alpha-889 regulatory region. The T genotypes of both have been reported to increase the risk of Alzheimer's disease (AD) (Arch. Neurol. 58 (2001) 1790). Since the lesions of PD and AD have similar neuroinflammatory characteristics (Neurology 38 (1988) 1285), we genotyped 100 PD and 100 control postmortem brains for the same polymorphisms. We found a significant increase of the IL-1 beta T genotype in PD cases compared with controls (chi(2)=9.65, P=0.0019). A significant increase was not found for the IL-alpha T genotype (chi(2)=1.32, P=0.23), although there was a trend towards more frequent expression of the T allele

43. Michel PP, Hirsch EC, Agid Y (2002) [Parkinson's disease: cell death mechanisms]. Rev.Neurol.(Paris) 158:24-32
    Abstract: Parkinson disease is a neurodegenerative disorder of aging characterized by a selective and progressive loss of dopaminergic neurons within the substantia nigra. The diagnosis of the disease is made when neuronal cell loss exceeds 50 p. cent indicating that the degenerative process started well before the onset of the first clinical symptoms. Three populations of dopaminergic neurons seem to coexist in the substantia nigra of Parkinsonian patients; (1) senescent neurons that are still spared by the pathological process; (2) sick neurons exhibiting generally a preserved morphology but showing evidence of biochemical and metabolic abnormalities; (3) neurons which have entered into a final state of agony and exhibit the hallmarks of apoptosis, a controlled form of cell death that requires the activation of a particular type of proteases, caspases. In the inherited forms of the disease that are caused by mutations of genes encoding the Parkin, alpha-synuclein and UCHL-1 proteins, the degenerative process results from the dysfunction of an enzymatic complex of proteolysis, the proteasome. This probably leads to the intracellular accumulation of abnormal proteins that become deleterious for dopaminergic neurons. In the sporadic forms of the disease that are the most frequent, causes of the cell demise remain still unknown but neurodegeneration might also result from a decreased activity of the proteasome. A defect in the detoxification of reactive oxygen species or an energy failure caused by inhibition of the mitochondrial respiratory chain, at the complex I level, are other hypothesis that are frequently mentioned. Finally, activated glial cells (astrocytes and Microglia) located around the degenerating dopaminergic neurons might also intervene in the mechanism of degeneration by perpetuating or even amplifying the primary neuronal insult. Proinflammatory cytokines acting on cell death membrane receptors and diffusable messengers such as nitric oxide could be part of this process

44. Michel PP, Hirsch EC, Agid Y (2002) [Parkinson disease: mechanisms of cell death]. Rev.Neurol.(Paris) 158 Spec no 1:S24-S32
    Abstract: Parkinson disease is a neurodegenerative disorder of aging characterized by a selective and progressive loss of dopaminergic neurons within the substantia nigra. The diagnosis of the disease is made when neuronal cell loss exceeds 50 p. 100 indicating that the degenerative process started well before the onset of the first clinical symptoms. Three populations of dopaminergic neurons seem to coexist in the substantia nigra of Parkinsonian patients; (1) senescent neurons that are still spared by the pathological process; (2) sick neurons exhibiting generally a preserved morphology but showing evidence of biochemical and metabolic abnormalities; (3) neurons which have entered into a final state of agony and exhibit the hallmarks of apoptosis, a controlled form of cell death that requires the activation of a particular type of proteases, caspases. In the inherited forms of the disease that are caused by mutations of genes encoding the Parkin, alpha-synuclein and UCHL-1 proteins, the degenerative process results from the dysfunction of an enzymatic complex of proteolysis, the proteasome. This probably leads to the intracellular accumulation of abnormal proteins that become deleterious for dopaminergic neurons. In the sporadic forms of the disease that are the most frequent, causes of the cell demise remain still unknown but neurodegeneration might also result from a decreased activity of the proteasome. A defect in the detoxification of reactive oxygen species or an energy failure caused by inhibition of the mitochondrial respiratory chain, at the complex I level, are other hypothesis that are frequently mentioned. Finally, activated glial cells (astrocytes and Microglia) located around the degenerating dopaminergic neurons might also intervene in the mechanism of degeneration by perpetuating or even amplifying the primary neuronal insult. Proinflammatory cytokines acting on cell death membrane receptors and diffusable messengers such as nitric oxide could be part of this process

45. Orr CF, Rowe DB, Halliday GM (2002) An inflammatory review of Parkinson's disease. Prog.Neurobiol. 68:325-340
    Abstract: The symptoms of Parkinson's disease (PD) were first described nearly two centuries ago and its characteristic pathology identified nearly a century ago, yet its pathogenesis is still poorly understood. Parkinson's disease is the most prevalent neurodegenerative movement disorder and research into its pathogenesis recently accelerated following the identification of a number of causal genetic mutations. The mutant gene products all cause dysfunction of the ubiquitin-proteosome system, identifying protein modification and degradation as critical for pathogenesis. Modified non-degraded intracellular proteins accumulate in certain neuronal populations in all forms of the disease. However, neuronal degeneration is more highly selective and associates with substantial activation of Microglia, the inflammatory cells of the brain. We review the current change in thinking regarding the role of Microglia in the brain in the context of Parkinson's disease and animal models of the disease. Comparison of the cellular tissue changes across a number of animal models using diverse stimuli to mimic Parkinson's disease reveals a consistent pattern implicating Microglia as the effector for the selective degeneration of dopaminergic neurons. While previous reviews have concentrated on the intracellular neuronal changes in Parkinson's disease, we highlight the cell to cell interactions and immune regulation critical for neuronal homeostasis and survival in Parkinson's disease

46. Ryu JK, Shin WH, Kim J, Joe EH, Lee YB, Cho KG, Oh YJ, Kim SU, Jin BK (2002) Trisialoganglioside GT1b induces in vivo degeneration of nigral dopaminergic neurons: role of Microglia. Glia 38:15-23
    Abstract: We recently showed that trisialoganglioside (GT1b) induces cell death of dopaminergic neurons in rat mesencephalic cultures (Chung et al., Neuroreport 12:611-614, 2001). The present study examines the in vivo neurotoxic effects of GT1b on dopaminergic neurons in the substantia nigra (SN) of Sprague-Dawley rats. Seven days after GT1b injection into the SN, immunocytochemical staining of SN tissue revealed death of nigral neurons, including dopaminergic neurons. Additional immunostaining using OX-42 and OX-6 antibodies showed that GT1b-activated Microglia were present in the SN where degeneration of nigral neurons was found. Western blot analysis and double-labeled immunohistochemistry showed that inducible nitric oxide synthase (iNOS) was expressed in the SN, where its levels were maximal at 8 h post-GT1b injection, and that iNOS was localized exclusively within Microglia. GT1b-induced loss of dopaminergic neurons in the SN was partially inhibited by N(G)-nitro-L-arginine methyl ester hydrochloride, an NOS inhibitor. Our results indicate that in vivo neurotoxicity of GT1b against nigral dopaminergic neurons is at least in part mediated by nitric oxide released from activated Microglia. Because GT1b exists abundantly in central nervous system neuronal membranes, our data support the hypothesis that immune-mediated events triggered by endogenous compounds such as GT1b could contribute to the initiation and/or the progression of dopaminergic neuronal cell death that occurs in Parkinson's disease

47. Sriram K, Matheson JM, Benkovic SA, Miller DB, Luster MI, O'Callaghan JP (2002) Mice deficient in TNF receptors are protected against dopaminergic neurotoxicity: implications for Parkinson's disease. FASEB J. 16:1474-1476
    Abstract: The pathogenic mechanisms underlying idiopathic Parkinson's disease (PD) remain enigmatic. Recent findings suggest that inflammatory processes are associated with several neurodegenerative disorders, including PD. Enhanced expression of the proinflammatory cytokine, tumor necrosis factor (TNF)-alpha, has been found in association with glial cells in the substantia nigra of patients with PD. To determine the potential role for TNF-alpha in PD, we examined the effects of the 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine (MPTP), a dopaminergic neurotoxin that mimics some of the key features associated with PD, using transgenic mice lacking TNF receptors. Administration of MPTP to wild-type (+/+) mice resulted in a time-dependent expression of TNF-alpha in striatum, which preceded the loss of dopaminergic markers and reactive gliosis. In contrast, transgenic mice carrying homozygous mutant alleles for both the TNF receptors (TNFR-DKO), but not the individual receptors, were completely protected against the dopaminergic neurotoxicity of MPTP. The data indicate that the proinflammatory cytokine TNF-alpha is an obligatory component of dopaminergic neurodegeneration. Moreover, because TNF-alpha is synthesized predominantly by Microglia and astrocytes, our findings implicate the participation of glial cells in MPTP-induced neurotoxicity. Similar mechanisms may underlie the etiopathogenesis of PD

48. Tomas-Camardiel M, Sanchez-Hidalgo MC, Sanchez del Pino MJ, Navarro A, Machado A, Cano J (2002) Comparative study of the neuroprotective effect of dehydroepiandrosterone and 17beta-estradiol against 1-methyl-4-phenylpyridium toxicity on rat striatum. Neuroscience 109:569-584
    Abstract: The effects of dehydroepiandrosterone, estradiol and testosterone on 1-methyl-4-phenylpyridium (MPP+)-induced neurotoxicity of the nigrostriatal dopaminergic system were examined in rat. They were subjected to a unilateral intrastriatal infusion of the following treatment conditions: MPP+ alone or co-injection of MPP+ plus each hormone. Four days after injection, concentrations of dopamine and their metabolites were determined from the corpus striatum. To corroborate the neurochemical data an immunohistochemical analysis of tyrosine hydroxylase-immunoreactive fibers and acetylcholinesterase histochemistry in the striatum was performed. Moreover, we performed a dose-response study of the three hormones on the high-affinity dopamine transport system in rat striatal synaptosomes.Rats co-injected within the striatum with MPP+ and either dehydroepiandrosterone or estradiol had significantly greater concentrations of dopamine and less tyrosine hydroxylase-immunoreactive fibers and acetylcholinesterase fiber density loss compared with their respective controls. In addition, 4 days after injection, the brain was fixed and cut into coronal sections, and was immunostained with major histocompatibility complex class II antigens for activated Microglia, and glial fibrillary acidic protein for activated astrocytes. Dehydroepiandrosterone also attenuated Microglial cell activation. In contrast, testosterone showed reductions in dopamine concentrations similar to those obtained by MPP+. The protective effect of dehydroepiandrosterone against the MPP+ neurotoxic dopaminergic system may be produced by its partial prevention of MPP+ inhibition of NADH oxidase activity, whereas the estradiol may function as a neuroprotectant by reducing the uptake of MPP+ into dopaminergic neurons.Our findings we suggest indicate that dehydroepiandrosterone and estradiol by a non-genomic effect may have an important modulatory action, capable of attenuating degeneration within the striatum, and in this way serve as neuroprotectants of the nigrostriatal dopaminergic system

49. Wu DC, Jackson-Lewis V, Vila M, Tieu K, Teismann P, Vadseth C, Choi DK, Ischiropoulos H, Przedborski S (2002) Blockade of Microglial activation is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson disease. J.Neurosci. 22:1763-1771
    Abstract: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) damages the nigrostriatal dopaminergic pathway as seen in Parkinson's disease (PD), a common neurodegenerative disorder with no effective protective treatment. Consistent with a role of glial cells in PD neurodegeneration, here we show that minocycline, an approved tetracycline derivative that inhibits Microglial activation independently of its antimicrobial properties, mitigates both the demise of nigrostriatal dopaminergic neurons and the formation of nitrotyrosine produced by MPTP. In addition, we show that minocycline not only prevents MPTP-induced activation of Microglia but also the formation of mature interleukin-1beta and the activation of NADPH-oxidase and inducible nitric oxide synthase (iNOS), three key Microglial-derived cytotoxic mediators. Previously, we demonstrated that ablation of iNOS attenuates MPTP-induced neurotoxicity. Now, we demonstrate that iNOS is not the only Microglial-related culprit implicated in MPTP-induced toxicity because mutant iNOS-deficient mice treated with minocycline are more resistant to this neurotoxin than iNOS-deficient mice not treated with minocycline. This study demonstrates that Microglial-related inflammatory events play a significant role in the MPTP neurotoxic process and suggests that minocycline may be a valuable neuroprotective agent for the treatment of PD

50. Wu dC, Tieu K, Cohen O, Choi DK, Vila M, Jackson-Lewis V, Teismann P, Przedborski S (2002) Glial cell response: A pathogenic factor in Parkinson's disease. J.Neurovirol. 8:551-558
    Abstract: Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The loss of these neurons is associated with a glial response composed mainly of activated Microglial cells and, to a lesser extent, of reactive astrocytes. This glial response may be the source of trophic factors and can protect against reactive oxygen species and glutamate. Alternatively, this glial response can also mediate a variety of deleterious events related to the production of pro-oxidant reactive species, proinflammatory prostaglandin, and cytokines. In this review, the authors discuss the potential protective and deleterious effects of glial cells in the SNpc of PD and examine how these factors may contribute to the pathogenesis of this disease

51. Armstrong RJ, Harrower TP, Hurelbrink CB, McLaughin M, Ratcliffe EL, Tyers P, Richards A, Dunnett SB, Rosser AE, Barker RA (2001) Porcine neural xenografts in the immunocompetent rat: immune response following grafting of expanded neural precursor cells. Neuroscience 106:201-216
    Abstract: Intracerebral neural xenografts elicit a host immune response that results in their rapid rejection. This forms a key barrier to the therapeutic use of xenogeneic tissue transplantation for conditions such as Parkinson's disease. The current study sought to provide insight into the cellular components of donor cell suspensions that are important in stimulating the host rejection response and thereby to suggest rational manipulations of xenogeneic donor tissue that might ultimately enhance its clinical utility. The neural stem cell mitogens, epidermal growth factor and fibroblast growth factor-2, have been used to isolate and expand populations of primordial neural precursor cells from the embryonic pig brain. The immune response elicited by these cells on transplantation into the non-immunosuppressed rat has been fully characterised.In the first experiments, expanded neural precursors were grafted into the hemi-Parkinsonian, non-immunosuppressed Sprague-Dawley rat and graft status and host response examined 10, 21, 35 and 60 days post-transplantation. While equivalent primary tissue grafts were completely eliminated at 35 days, grafts of expanded neural precursors with healthy neurofilament-positive projections were present at all time-points, and two large grafts remained even at 60 days. Some grafts appeared to elicit minimal host immune responses at the time-points they were examined, although most did appear to be undergoing a rejection process since a co-ordinated response involving host cytotoxic T-lymphocytes, Microglia/macrophages, immunoglobulin M and complement could be demonstrated to varying degrees.Subsequent experiments went on to demonstrate further that expanded precursor populations and primary tissue suspensions differed in their immunogenic profile. Firstly, when primary tissue was injected intraperitoneally into immunocompetent rats a vigorous primary humoral response was generated. No such response was detected following injection of expanded neural precursors. Secondly, flow cytometric analysis revealed small but significant levels of class II porcine major histocompatibility complex expression in primary cell suspensions but no such expression in expanded precursor populations.The results of this study therefore demonstrate that the immunogenicity of porcine neural cell suspensions used for intracerebral grafting is reduced when neural stem cell mitogens are used to expand precursor cells. The implications of these findings in the development of novel xenogeneic cellular therapies for neurodegenerative conditions such as Parkinson's disease are discussed

52. Berg D, Gerlach M, Youdim MB, Double KL, Zecca L, Riederer P, Becker G (2001) Brain iron pathways and their relevance to Parkinson's disease. J.Neurochem. 79:225-236
    Abstract: A central role of iron in the pathogenesis of Parkinson's disease (PD), due to its increase in substantia nigra pars compacta dopaminergic neurons and reactive Microglia and its capacity to enhance production of toxic reactive oxygen radicals, has been discussed for many years. Recent transcranial ultrasound findings and the observation of the ability of iron to induce aggregation and toxicity of alpha-synuclein have reinforced the critical role of iron in the pathogenesis of nigrostriatal injury. Presently the mechanisms involved in the disturbances of iron metabolism in PD remain obscure. In this review we summarize evidence from recent studies suggesting disturbances of iron metabolism in PD at possibly different levels including iron uptake, storage, intracellular metabolism, release and post-transcriptional control. Moreover we outline that the interaction of iron with other molecules, especially alpha-synuclein, may contribute to the process of neurodegeneration. Because many neurodegenerative diseases show increased accumulation of iron at the site of neurodegeneration, it is believed that maintenance of cellular iron homeostasis is crucial for the viability of neurons

53. Brevig T, Meyer M, Kristensen T, Zimmer J, Holgersson J (2001) Xenotransplantation for brain repair: reduction of porcine donor tissue immunogenicity by treatment with anti-Gal antibodies and complement. Transplantation 72:190-196
    Abstract: BACKGROUND: Transplantation of embryonic neural tissue is a potential treatment for Parkinson's disease. Because human donor material is in short supply, porcine xenografts are considered a useful alternative. Current immunosuppressive therapies fail, however, to protect intracerebral neural xenografts from host CD4 T lymphocytes. To reduce the immunogenicity of porcine donor tissue, we attempted to remove Microglial cells with antibodies against the alpha-galactosyl epitope (Galalpha1,3Galbeta1,4GlcNAc-R), or anti-Gal, and complement, and studied whether this pretreatment can reduce direct and indirect T-cell responses to the tissue. METHODS: Brain tissue from 27-day-old pig embryos was dissociated and treated with human anti-Gal and rabbit complement. The Microglial content was analyzed by flow cytometry. [3H]thymidine incorporation in cocultures of the brain cells and purified human CD4 T cells was used to determine direct T-cell responses. Indirect T-cell responses were studied by grafting pretreated and control-pretreated (no anti-Gal) nigral tissue into the lesioned striatum of immunocompetent rats with 6-hydroxydopamine-induced hemiParkinsonism. Amphetamine-induced circling behavior was used to measure graft function. RESULTS: Anti-Gal and complement reduced the Microglial content to 11-24% of control and abolished the ability of the brain cells to induce human CD4 T-cell proliferation. Pretreated nigral tissue reduced hemiParkinsonism by more than 50% in five of eight rats at some point during the 10-week follow-up. Rats receiving control-pretreated nigral tissue did not display this degree of improvement. CONCLUSIONS: Pretreatment with anti-Gal and complement can reduce the immunogenicity of porcine neural tissue, and might, therefore, be a valuable alternative or supplement to immunosuppression in neural xenotransplantation

54. Brevig T, Meyer M, Kristensen T, Zimmer J (2001) Neural xenotransplantation: pretreatment of porcine embryonic nigral tissue with anti-Gal antibodies and complement is not toxic for the dopaminergic neurons. Cell Transplant. 10:25-30
    Abstract: The immunogenicity of porcine tissue is a major obstacle to its use as donor material in xenotransplantation for neurodegenerative diseases. We are currently evaluating a novel strategy for reducing the immunogenicity, in which the alpha-galactosyl epitope (Galalpha1,3Galbeta1,4GlcNAc-R) is used as a target for antibody- and complement-mediated removal of Microglia. In the present study, our aim was to determine whether a pretreatment with antibodies against the alpha-galactosyl epitope (anti-Gal) and complement would lyse or otherwise damage dopaminergic neurons in porcine embryonic ventral mesencephalon (VM), the donor tissue for treatment of Parkinson's disease by xenotransplantation. Cell suspensions prepared from VM tissue from 27-day-old pig embryos were incubated with anti-Gal, purified from normal human serum by affinity chromatography, or medium only (control), and subsequently with rabbit complement. After these pretreatments, the cell suspensions were transplanted into the right striatum of 14 adult rats (two groups of 7 animals). The animals were sacrificed 20 days after transplantation, the brains were processed for histology, and the sections were stained for Nissl substance, porcine neurofilament, tyrosine hydroxylase, and rat CD45 to determine graft volume, presence of porcine neurons, content of dopaminergic cells, and leukocyte infiltration, respectively. The VM tissue pretreated with anti-Gal and complement gave rise to dopaminergic grafts that were indistinguishable from those derived from VM tissue given the control pretreatment. In 5 of the 14 animals, the grafts were infiltrated by host leukocytes, but in two of these recipients, the infiltration was only minimal. We conclude that anti-Gal and complement can be applied to porcine embryonic VM tissue without damaging the dopaminergic neurons and their precursors

55. Czlonkowska A, Kurkowska-Jastrzebska I (2001) [Treatment of neurodegenerative diseases: new perspectives]. Neurol.Neurochir.Pol. 35:147-156
    Abstract: The experimental models of neurodegeneration give a possibility to study the inflammatory reaction that starts in response to neuronal death. Inflammation consists of Microglial and astroglial activation, expression of new molecules as cytokines, adhesion molecules and MHC antigens, and is potentially neurotoxic. This article is a summary of a few latest studies that investigate anti-inflammatory agents effect on neuron survival in MPTP mice model of Parkinson's disease. Murine model of Parkinson's disease uses a quite selective toxic effect of MPTP on nigrostriatal system. MPTP causes degeneration of dopaminergic cells bodies in the substantia nigra and of their endings in striatum. Our findings show that anti-inflammatory treatment protects neuronal death. It may indicate that the inflammation contributes to the dopaminergic neuron impairment following MPTP intoxication. However this hypothesis needs further investigation because recent studies suggest that inflammation may have also a protective effect in neurodegentration

56. Fillebeen C, Ruchoux MM, Mitchell V, Vincent S, Benaissa M, Pierce A (2001) Lactoferrin is synthesized by activated Microglia in the human substantia nigra and its synthesis by the human Microglial CHME cell line is upregulated by tumor necrosis factor alpha or 1-methyl-4-phenylpyridinium treatment. Brain Res.Mol.Brain Res. 96:103-113
    Abstract: The presence of the iron-binding protein lactoferrin (Lf) in some specific areas of the central nervous system and particularly in the normal human substantia nigra, where it is found in dopaminergic (DA) neurons and some glial cells, led us to investigate Lf synthesis in this area. Lf mRNA were identified using in situ hybridization and found in small ameboid cells. These cells were identified using immunocytochemistry as activated Microglia since they exhibited macrophage markers such as the CD68 and the CR1 antigens. Double immunofluorescent labeling confirmed that the two Lf immunostained cell populations were activated Microglia and DA neurons. Since activated Microglia contained both Lf and its messenger, these cells are the Lf producing cells. The presence of Lf in DA neurons in which no Lf messengers were visible, might be due to an endocytosis mechanism, DA neurons probably internalizing Lf produced in Microglial cells located in their neighborhood. In neuropathological disorders, such as Alzheimer's and Parkinson's diseases, inflammatory process and oxidative stress are events that contribute to neuronal death. Since Lf concentration increases during these pathologies, we studied the level of Lf expression under these different stresses and showed, using RT-PCR, that the immortalized human embryonic Microglial CHME cell line produced Lf transcripts under tumor necrosis factor alpha or 1-methyl-4-phenylpyridinium treatment whereas untreated cells did not. These data confirm that Lf is produced only when Microglia are activated

57. Fiszer U (2001) Does Parkinson's disease have an immunological basis? The evidence and its therapeutic implications. BioDrugs. 15:351-355
    Abstract: Parkinson's disease (PD) is an age-related neurodegenerative movement disorder of unknown aetiology. Immune abnormalities have been described in PD including the occurrence of autoantibodies against neuronal structures and high numbers of Microglia cells expressing the histocompatibility glycoprotein human leucocyte antigen-DR in the substantia nigra. An infectious cause for PD has been discussed for years. Disturbed cellular and humoral immune functions in peripheral blood of patients with PD have been also reported. An elevated gammadelta(+) T cell population and increased immunoglobulin G immunity in CSF to heat shock proteins have been found in PD. Cytokines and apoptosis-related proteins were elevated in the striatum in patients with PD. Activated glial cells may participate in neuronal cell death in PD by providing toxic substances. We may conclude that the immune system is involved in the pathogenesis of PD. However, we are not able to determine whether the disturbances described above constitute a primary or secondary phenomenon. Immunomodulatory agents may have important applications in the development of new therapies for PD

58. He Y, Appel S, Le W (2001) Minocycline inhibits Microglial activation and protects nigral cells after 6-hydroxydopamine injection into mouse striatum. Brain Res. 909:187-193
    Abstract: To determine the role of immune/inflammatory factors in dopaminergic cell degeneration in Parkinsonian substantia nigra, we assayed tyrosine hydroxylase (TH)-positive immunoreactive neuronal numbers with stereologic techniques and CD11b-positive immunoreactive Microglial profiles following 6-hydroxydopamine (6-OHDA) injection into ipsilateral striatum of mice. We further investigated the effect of minocycline on the inhibition of Microglial activation and subsequent protection of nigral cells. The relative number of Microglial profiles in the substantia nigra (SN) ipsilateral to the injection increased from 31 to 32% 1-3 days after injection, and increased further to 55% by 7 days and 59% by 14 days, compared with the contralateral SN. These changes started prior to the decrease of TH immunoreactivity of 34% on day 7 and of 42% by day 14. In animals treated with minocycline, Microglial activation was inhibited by 47%, and TH positive cells were protected by 21% at day 14 after 6-OHDA injection, compared with those Parkinsonian animals without minocycline treatment. All these results suggest that Microglial activation may be involved in the nigral cell degeneration in 6-OHDA induced Parkinsonian mice

59. Le W, Rowe D, Xie W, Ortiz I, He Y, Appel SH (2001) Microglial activation and dopaminergic cell injury: an in vitro model relevant to Parkinson's disease. J.Neurosci. 21:8447-8455
    Abstract: Microglial activation and oxidative stress are significant components of the pathology of Parkinson's disease (PD), but their exact contributions to disease pathogenesis are unclear. We have developed an in vitro model of nigral injury, in which lipopolysaccharide-induced Microglial activation leads to injury of a dopaminergic cell line (MES 23.5 cells) and dopaminergic neurons in primary mesencephalic cell cultures. The Microglia are also activated by PD IgGs in the presence of low-dose dopa-quinone- or H(2)O(2)-modified dopaminergic cell membranes but not cholinergic cell membranes. The activation requires the Microglial FCgammaR receptor as demonstrated by the lack of activation with PD IgG Fab fragments or Microglia from FCgammaR-/- mice. Although Microglial activation results in the release of several cytokines and reactive oxygen species, only nitric oxide and H(2)O(2) appear to mediate the Microglia-induced dopaminergic cell injury. These studies suggest a significant role for Microglia in dopaminergic cell injury and provide a mechanism whereby immune/inflammatory reactions in PD could target oxidative injury relatively specifically to dopaminergic cells

60. Satoh JI, Kuroda Y (2001) Alpha-synuclein expression is up-regulated in NTera2 cells during neuronal differentiation but unaffected by exposure to cytokines and neurotrophic factors. Parkinsonism.Relat Disord. 8:7-17
    Abstract: Increasing evidence has indicated that proinflammatory cytokines such as TNF-alpha and IL-1beta, produced by activated Microglia and astrocytes, play a key role in progressive degeneration of the nigrostriatal dopaminergic neurons in Parkinson's disease (PD). Since alpha-synuclein is a major component of Lewy bodies in PD brains, we studied the constitutive and cytokine/neurotrophic factor-regulated expression of alpha-synuclein in cultured human neurons by Northern blot and Western blot analyses. The constitutive expression of alpha-synuclein mRNA was identified in a variety of human neural and non-neural cell lines. The levels of alpha-synuclein expression were elevated markedly in NTera2 teratocarcinoma cells following retinoic acid-induced neuronal differentiation, accompanied with an increased expression of synphilin-1, while they were unaltered in NTera2-derived differentiated neurons by exposure to TNF-alpha, IL-1beta, BDNF or GDNF. These results indicate that alpha-synuclein expression in human neurons is up-regulated during differentiation, but is unaffected by a panel of cytokines and neurotrophic factors which are supposed to be involved in the nigral neuronal death and survival

61. Vila M, Jackson-Lewis V, Guegan C, Wu DC, Teismann P, Choi DK, Tieu K, Przedborski S (2001) The role of glial cells in Parkinson's disease. Curr.Opin.Neurol. 14:483-489
    Abstract: Parkinson's disease is a common neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons in the substantia nigra pars compacta. The loss of these neurons is associated with a glial response composed mainly of activated Microglial cells and, to a lesser extent, of reactive astrocytes. This glial response may be the source of trophic factors and can protect against reactive oxygen species and glutamate. Aside from these beneficial effects, the glial response can mediate a variety of deleterious events related to the production of reactive species, and pro-inflammatory prostaglandin and cytokines. This article reviews the potential protective and deleterious effects of glial cells in the substantia nigra pars compacta of Parkinson's disease

62. Yasojima K, Tourtellotte WW, McGeer EG, McGeer PL (2001) Marked increase in cyclooxygenase-2 in ALS spinal cord: implications for therapy. Neurology 57:952-956
    Abstract: OBJECTIVE: To evaluate the hypothesis that cyclooxygenase-2 (COX-2) is linked to the pathology of ALS by determining whether COX-2 mRNA levels are upregulated in ALS spinal cord. METHODS: Spinal cord from 11 ALS cases and 27 controls consisting of 15 cases of Alzheimer disease (AD), six cases of Parkinson disease (PD), three cases of cerebrovascular disease, and three control cases were analyzed. Total RNA was extracted and reverse transcriptase-PCR analysis performed for the mRNA of COX-2, COX-1, the Microglial marker CD11b, and the housekeeping gene cyclophilin. RESULTS: In ALS compared with non-ALS spinal cord, COX-2 mRNA was upregulated 7.09-fold (p < 0.0001), COX-1 1.14-fold (p = 0.05), and CD11b 1.85-fold (p = 0.0012). COX-2 mRNA levels in AD, PD, cerebrovascular disease, and control cases were each significantly lower than in ALS and were not significantly different from each other. Western blots of the protein products were in general accord with the mRNA data, with COX-2 protein levels being upregulated 3.79-fold compared with non-ALS cases (p = 0.015). CONCLUSIONS: The strong upregulation of COX-2 mRNA in ALS is in accord with studies in the superoxide dismutase transgenic mouse model in which COX-2 upregulation occurs. Taken in conjunction with evidence of a neuroprotective effect of COX-2 inhibitors in certain animal models and in organotypic cultures, the data are supportive of a possible future role for COX-2 inhibitors in the treatment of ALS

63. Grunblatt E, Mandel S, Youdim MB (2000) MPTP and 6-hydroxydopamine-induced neurodegeneration as models for Parkinson's disease: neuroprotective strategies. J.Neurol. 247 Suppl 2:II95-102
    Abstract: The etiology of Parkinson's disease is not known. Nevertheless, a significant body of biochemical data from human brain autopsy studies and from animal models points to an ongoing process of oxidative stress in the substantia nigra, which could initiate dopaminergic neurodegeneration. It is not known whether oxidative stress is a primary or secondary event. Oxidative stress, as induced by the neurotoxins 6-hydroxydopamine and MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), has been used in animal models to investigate the process of neurodegeneration to facilitate the development of antioxidant, neuroprotective drugs. It is apparent in these animal models that radical scavengers, iron chelators, dopamine agonists, nitric oxide synthase inhibitors and certain calcium channel antagonists provide neuroprotection against such toxins if given prior to the insult. Furthermore, recent work from human and animal studies has provided evidence of an inflammatory process. This expresses itself as proliferation of activated Microglia in the substantia nigra, activation and translocation of transcription factors and neurotrophic factor (NF), kappa-beta and elevation of cytotoxic cytokines, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6. Both radical scavengers and iron chelators prevent lipopolysaccharide (LPS) and iron-induced activation of NF kappa-beta. If an inflammatory response is involved in Parkinson's disease, it would be logical to consider antioxidants and the newly developed, non-steroidal, anti-inflammatory drugs such as cyclo-oxygenase (COX2) inhibitors as a form of treatment. However, to date there has been little or no success in the clinical treatment of neurodegenerative diseases (for example, Parkinson's disease, ischaemia etc.) where neurons die, while in animal models the same drugs provide neuroprotection. This may indicate that either the animal models employed do not reflect the events in neurodegenerative diseases, or that because neuronal death involves a cascade of events, a single neuroprotective drug is not effective. Thus, consideration should be given to multi-neuroprotective drug therapy in Parkinson's disease, similar to the approach taken in AIDS and cancer therapy

64. Grunblatt E, Mandel S, Youdim MB (2000) Neuroprotective strategies in Parkinson's disease using the models of 6-hydroxydopamine and MPTP. Ann.N.Y.Acad.Sci. 899:262-273
    Abstract: The etiology of Parkinson's disease is not known. Nevertheless a significant body of biochemical data from human brain autopsy studies and those from animal models point to an on going process of oxidative stress in the substantia nigra which could initiate dopaminergic neurodegeneration. It is not known whether oxidative stress is a primary or secondary event. Nevertheless, oxidative stress as induced by neurotoxins 6-hydroxydopamine and MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) has been used in animal models to investigate the process of neurodegeneration with intend to develop antioxidant neuroprotective drugs. It is apparent that in these animal models radical scavengers, iron chelators, dopamine agonists, nitric oxide synthase inhibitors and certain calcium channel antagonists do induce neuroprotection against such toxins if given prior to the insult. Furthermore, recent work from human and animal studies has provided also evidence for an inflammatory process. This expresses itself by proliferation of activated Microglia in the substantia nigra, activation and translocation of transcription factors, NF kappa-beta and elevation of cytotoxic cytokines TNF alpha, IL1-beta, and IL6. Both radical scavengers and iron chelators prevent LPS (lipopolysaccharide) and iron induced activation of NF kappa-B. If an inflammatory response is involved in Parkinson's disease it would be logical to consider antioxidants and the newly developed non-steroid anti-inflammatory drugs such as COX2 (cyclo-oxygenase) inhibitors as a form of treatment. However to date there has been little or no success in the clinical treatment of neurodegenerative diseases per se (Parkinson's disease, ischemia etc.), where neurons die, while in animal models the same drugs produce neuroprotection. This may indicate that either the animal models employed are not reflective of the events in neurodegenerative diseases or that because neuronal death involves a cascade of events, a single neuroprotective drug would not be effective. Thus, consideration should be given to multi-neuroprotective drug therapy in Parkinson's disease, similar to the approach taken in AIDS and cancer therapy

65. Herrera AJ, Castano A, Venero JL, Cano J, Machado A (2000) The single intranigral injection of LPS as a new model for studying the selective effects of inflammatory reactions on dopaminergic system. Neurobiol.Dis. 7:429-447
    Abstract: We have injected lipopolysaccharide (LPS) into the nigrostriatal pathway of rats in order to address the role of inflammation in Parkinson's disease (PD). LPS induced a strong macrophage/Microglial reaction in Substantia nigra (SN), with a characteristic clustering of macrophage cells around blood-vessels. The SN was far more sensitive than the striatum to the inflammatory stimulus. Moreover, only the dopaminergic neurons of the SN were affected, with no detectable damage to either the GABAergic or the serotoninergic neurons. The damage to the DA neurons in the SN was permanent, as observed 1 year postinjection. Unlike the direct death of dopaminergic neurons caused by agents as MPP(+) or 6-OHDA, LPS seems to cause indirect death due to inflammatory reaction. Therefore, we suggest that the injection of a single dose of LPS within the SN is an interesting model for studying the selective effects of inflammatory reaction on dopaminergic system and also potentially useful for studying PD

66. Jellinger KA (2000) Cell death mechanisms in Parkinson's disease. J.Neural Transm. 107:1-29
    Abstract: OBJECTIVE: While the causes of neuronal death in Parkinson's disease (PD) and other neurodegenerative disorders are still unknown, several mechanisms are under discussion: programmed vs. passive cell death (apoptosis vs. necrosis), mainly based on conflicting results on the rare presence or absence of DNA fragmentation in substantia nigra neurons using the in situ DNA-labeling (TUNEL) method. DESIGN/METHODS: In 4 cases of Parkinson's disease (PD), 2 cases of Dementia with Lewy bodies (DLB) and 3 age-matched controls, the TUNEL/ISEL method was used to detect DNA fragmentation in substantia nigra locus coeruleus and cerebral cortex [method by Gold et al. (1994)]. In addition, immunohistochemistry was performed for an array of apoptosis-related proteins, i.e. the recently described apoptosis specific protein cJun/AP1 (ASP), the proto-oncogenes c-Jun, c-Jun AP1, Bcl2, Bax, Bcl-x, p53, CD 95 (Fas/Apo-1), activated caspase 3, several heat shock proteins (alpha-B crystallin, ubiquitin), and alpha-synuclein. RESULTS: None of the cases of PD, DLB, and controls showed convincing TUNEL-positivity nor morphologic signs of apoptosis in nigral, locus coeruleus or cortical neurons with or without Lewy bodies but variable numbers of TUNEL-positive astrocytes and Microglial cells in substantia nigra of PD and DLB. There were no significant differences in the expression of c-Jun, ASP, Bcl-2, Bax, and Bcl-x in substantia nigra neurons between PD, DLB, and controls nor between cortical and subcortical neurons with and without Lewy bodies. No expression of p53, and activated caspase 3, or any of the examined stress proteins was seen in neurons, while reactive astroglia and Microglia were decorated by antibodies to Bcl-2, Bax, alpha-B-crystallin and less, to Bcl-x and caspase 3. Lewy bodies, dystrophic neurites and axonal spheroids, all being negative for the applied apoptosis regulating proteins, showed strong expression of the examined stress proteins and of alpha-synuclein. CONCLUSIONS: These findings which are in line with previous results in Alzheimer's disease (Stadelmann et al., 1998) and Parkinson's disease (Banati et al., 1999) suggest that mechanisms distinct from classical apoptosis play a central role in the pathogenesis of PD and related neurodegenerative diseases. Further studies are warranted to elucidate the intracellular cascade of events leading to cell death in these disorders showing slow progression over many years

67. Jellinger KA, Stadelmann CH (2000) The enigma of cell death in neurodegenerative disorders. J.Neural Transm.Suppl21-36
    Abstract: Progressive cell loss in specific neuronal populations is the pathological hallmark of neurodegenerative diseases, but its mechanisms remain unresolved. Apoptotic cell death has been implicated as a major mechanism in Alzheimer disease (AD), Parkinson disease (PD) and other neurodegenerative disorders. However, DNA fragmentation in human brain as a sign of neuronal cell injury is too frequent to account for the continuous loss in these slowly progressive diseases. In a series of autopsy confirmed cases of AD, PD, related disorders, and age-matched controls, DNA fragmentation using the TUNEL method, an array of apoptosis-related proteins (ARP), proto-oncogenes, and activated caspase-3, the key enzyme of late-stage apoptosis, were examined. In AD, a considerable number of hippocampal neurons and glial cells showed DNA fragmentation with a 3- to 6-fold increase related to neurofibrillary tangles and amyloid deposits, but only 1 in 2.600 to 5.600 neurons displayed apoptotic morphology and cytoplasmic immunoreactivity for activated caspase-3, whereas no neurons were labeled in age-matched controls. caspase-3 immunoreactivity was seen in granules of cells with granulovacuolar degeneration, in around 25% co-localized with early cytoplasmic deposition of tau-protein. In progressive supranuclear palsy, only single neurons and several oligodendrocytes in brainstem, some with tau-deposits, were TUNEL-positive and expressed both ARPs and activated caspase-3. In PD, dementia with Lewy bodies, multisystem atrophy (MSA), and corticobasal degeneration, TUNEL-positivity and expression of ARPs or activated caspase-3 were only seen in Microglia and oligodendrocytes with cytoplasmic inclusions, but not in neurons. These data provide evidence for extremely rare apoptotic neuronal death in AD and PSP compatible with the progression of neuronal degeneration in these chronic diseases. Apoptosis mainly involves reactive Microglia and oligodendroglia, the latter often involved by deposits of insoluble fibrillary proteins, while alternative mechanisms of neuronal death may occur. Susceptible cell populations in a proapoptotic environment show increased vulnerability towards metabolic or other noxious factors, with autophagy as a possible protective mechanism in early stages of programmed cell death. The intracellular cascade leading to cell death still awaits elucidation

68. Jellinger KA, Stadelmann C (2000) Mechanisms of cell death in neurodegenerative disorders. J.Neural Transm.Suppl 59:95-114
    Abstract: OBJECTIVE: Progressive cell loss in specific neuronal populations is the prominent pathological hallmark of neurodegenerative diseases, but its molecular basis remains unresolved. Apoptotic cell death has been implicated as a general mechanism in Alzheimer disease (AD) and other neurodegenerative disorders. However, DNA fragmention in neurons is too frequent to account for the continuous loss in these slowly progressive diseases. MATERIAL AND METHODS: In 9 cases of morphologically confirmed AD (CERAD criteria, Braak stages 5 or 6), 5 cases of Parkinson disease (PD) and 3 cases each of Dementia with Lewy bodies (DLB), Progressive Supranuclear Palsy (PSP), and Multiple System Atrophy (MSA), and 7 age-matched controls, the TUNEL method was used to detect DNA fragmentation, and immunohistochemistry for an array of apoptosis-related proteins (ARP), protooncogenes, and activated caspase-3 were performed. RESULTS: In AD, a considerable number of hippocampal neurons showed DNA fragmentation with a 3 to 5.7 fold increase related to neurofibrillary tangles and amyloid deposits, but only exceptional neurons displayed apoptotic morphology (1 in 1100-5000) and cytoplasmic immunoreactivity for ARPs and activated caspase-3 (1 in 2600 to 5650 hippocampal neurons), whereas no neurons were labeled in age-matched controls. Caspase-3 immunoreactivity was seen in granules of granulovacuolar degeneration, only rarely colocalized with tau-immunoreactivity. In PD, DLB, and MSA, TUNEL positivity and expression of ARPs or activated caspase-3 was only seen in Microglia, rare astrocytes and in oligodendroglia with cytoplasmic inclusions in MSA, but not in nigral or other neurons with or without Lewy bodies. In PSP, only single neurons but oligodendrocytes, some with tau deposits, in brainstem tegmentum and pontine nuclei were TUNEL-positive and expressed both ARPs and activated caspase-3. CONCLUSIONS: These data provide evidence for extremely rare apoptotic neuronal death in AD compatible with the progression of neuronal degeneration in this chronic disease. In other neurodegenerative disorders, apoptosis mainly involves Microglia and oligodendroglia, while alternative mechanisms of neuronal death may occur. Susceptible cell populations in a proapoptotic environment show increased vulnerability towards metabolic and other pathogenic factors, with autophagy as a possible protective mechanism in early stages of programmed cell death. The intracellular cascade leading to cell death still awaits elucidation

69. Knott C, Stern G, Wilkin GP (2000) Inflammatory regulators in Parkinson's disease: iNOS, lipocortin-1, and cyclooxygenases-1 and -2. Mol.Cell Neurosci. 16:724-739
    Abstract: Degeneration of dopaminergic neurons and focal gliosis are pathological hallmarks of Parkinson's disease and although the brain is described as immune-privileged focal immune reactions surround failing nigral neurons. We examined the cellular distribution of pro- and anti-inflammatory molecules in human Parkinsonian and neurologically normal substantia nigra and caudate-putamen postmortem. An up-regulation of nitric oxide synthase- and cyclo-oxygenase-1- and -2-containing amoeboid Microglia was found in Parkinsonian but not control nigra. Astroglia contained low levels of these molecules in both groups. Lipocortin-1-immunoreactive amoeboid Microglia were present within the astrocytic envelope of neurons adjacent to or within glial scars in Parkinsonian nigra only. Lipocortin-1 is known to have neuroprotective and anti-inflammatory properties. Up-regulation of nitric oxide synthase is generally associated with neurodestruction whereas prostaglandin synthesis may be either neurodestructive or protective. The balance of these molecules is likely to be decisive in determining neuronal survival or demise

70. Larsson LC, Czech KA, Brundin P, Widner H (2000) Intrastriatal ventral mesencephalic xenografts of porcine tissue in rats: immune responses and functional effects. Cell Transplant. 9:261-272
    Abstract: Transplantation of neural tissue from other species has the potential to improve function in patients with neurodegenerative disorders. We investigated the functional effects of embryonic porcine dopaminergic neurons transplanted in a rat model of Parkinson's disease and the immune responses to the grafts in immunosuppressed and nonimmunosuppressed hosts. Twenty-three rats with unilateral 6-hydroxydopamine lesions received dissociated, 27-day-old embryonic porcine ventral mesencephalic tissue in the right striatum. Eighteen rats received cyclosporine (10 mg/kg, IP, daily) during the whole period of 14 weeks, in combination with prednisolone (20 mg/kg, IP, daily) the first 4 days. Five rats served as nonimmunosuppressed controls. All rats were tested for amphetamine-induced rotational behavior at 3-week intervals. Two immunosuppressed rats were excluded due to severe side effects of the treatment. Functional recovery was seen in 9 of 16 immunosuppressed rats at 12 weeks. Six animals remained functionally recovered at 14 weeks and contained an average of 5750+/-1450 (SEM) dopaminergic neurons. Between 9 and 14 weeks, three immunosuppressed rats rejected their grafts, based on rotation scores and immunohistochemical demonstration of cell infiltrates. One additional immunosuppressed rat showed evidence of ongoing rejection at 14 weeks. The striata in animals with ongoing or recent rejection contained large numbers of CD4- and CD8-positive lymphocytes, NK cells, macrophages, and Microglia cells, whereas scar tissue was found in rats with grafts rejected at earlier time points (n = 11). Embryonic porcine ventral mesencephalic tissue matures in the adult rat striatum, reinnervates the host brain, and restores behavioral defects. Immunosuppressive treatment was necessary for long-term graft survival and functional recovery, but did not sufficiently protect from rejection mechanisms. Porcine neural tissue is an interesting alternative to embryonic human tissue for intracerebral transplantation in neurodegenerative diseases. However, to achieve stable graft survival in discordant xenogeneic combinations, an appropriate immunosuppressive treatment or donor tissue modifications are needed

71. Lee CK, Weindruch R, Prolla TA (2000) Gene-expression profile of the ageing brain in mice. Nat.Genet. 25:294-297
    Abstract: Ageing of the brain leads to impairments in cognitive and motor skills, and is the major risk factor for several common neurological disorders such as Alzheimer disease (AD) and Parkinson disease (PD). Recent studies suggest that normal brain ageing is associated with subtle morphological and functional alterations in specific neuronal circuits, as opposed to large-scale neuronal loss. In fact, ageing of the central nervous system in diverse mammalian species shares many features, such as atrophy of pyramidal neurons, synaptic atrophy, decrease of striatal dopamine receptors, accumulation of fluorescent pigments, cytoskeletal abnormalities, and reactive astrocytes and Microglia. To provide the first global analysis of brain ageing at the molecular level, we used oligonucleotide arrays representing 6,347 genes to determine the gene-expression profile of the ageing neocortex and cerebellum in mice. Ageing resulted in a gene-expression profile indicative of an inflammatory response, oxidative stress and reduced neurotrophic support in both brain regions. At the transcriptional level, brain ageing in mice displays parallels with human neurodegenerative disorders. Caloric restriction, which retards the ageing process in mammals, selectively attenuated the age-associated induction of genes encoding inflammatory and stress responses

72. Mirza B, Hadberg H, Thomsen P, Moos T (2000) The absence of reactive astrocytosis is indicative of a unique inflammatory process in Parkinson's disease. Neuroscience 95:425-432
    Abstract: Virtually any neurological disorder leads to activation of resident Microglia and invasion of blood-borne macrophages, which are accompanied by an increase in number and change in phenotype of astrocytes, a phenomenon generally termed reactive astrocytosis. One of the functions attributed to activation of astrocytes is thought to involve restoration of tissue damage. Hitherto, the role of astrocytes in the inflammatory reaction occurring in Parkinson's disease has not received much attention. In the present study, we examined the inflammatory events in autopsies of the substantia nigra and putamen from Parkinson's disease patients using age-matched autopsies from normal patients as controls. In the substantia nigra, activation of Microglia was consistently observed in all Parkinson's disease autopsies as verified from immunohistochemical detection of CR3/43 and ferritin. Activation of resident Microglia was not observed in the putamen. No differences were observed between controls and Parkinson's disease autopsies from the substantia nigra and putamen, in terms of distribution, cellular density or cellular morphology of astrocytes stained for glial fibrillary acidic protein or metallothioneins I and II, the latter sharing high affinity for metal ions and known to be induced in reactive astrocytes, possibly to exert anti-oxidative effects. Together, these findings indicate that the inflammatory process in Parkinson's disease is characterized by activation of resident Microglia without reactive astrocytosis, suggesting that the progressive loss of dopaminergic neurons in Parkinson's disease is an ongoing neurodegenerative process with a minimum of involvement of the surrounding nervous tissue. The absence of reactive astrocytosis in Parkinson's disease contrasts what follows in virtually any other neurological disorder and may indicate that the inflammatory process in Parkinson's disease is a unique phenomenon

73. Ogawa K, Yamada T, Tsujioka Y, Taguchi J, Takahashi M, Tsuboi Y, Fujino Y, Nakajima M, Yamamoto T, Akatsu H, Mitsui S, Yamaguchi N (2000) Localization of a novel type trypsin-like serine protease, neurosin, in brain tissues of Alzheimer's disease and Parkinson's disease. Psychiatry Clin.Neurosci. 54:419-426
    Abstract: Neurosin, a novel type of trypsin-like serine protease, has been shown to be preferentially expressed in human brain by northern blotting. We examined neurosin immunolabeling in the brains of neurologically normal persons and patients with Alzheimer's disease (AD) and with Parkinson's disease. We also identified the expression of the mRNA for neurosin by in situ hybridization histochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The neurosin antibody stained all of the nuclei of various cell types. In neurons, there was also staining of neuronal cytoplasm, nucleoli and their processes. In AD, staining of neurons with processes was rare in the damaged areas. Some senile plaques, extracellular tangles and Lewy bodies were also positive for neurosin. Expression of the mRNA for neurosin was seen in neurons in the gray matter, and in Microglial cells in the white matter. In AD, the intensity of the signal for neurosin mRNA in the gray matter was decreased compared with normal control brains. The relative levels of neurosin mRNA in AD brains, measured by RT-PCR, were lower than those in controls. These results suggest that in human brain neurosin plays various physiological roles, and that in AD this molecule, like other serine proteases, may have a role in the degradation of such substances as beta-amyloid protein

74. Rozemuller AJ, Eikelenboom P, Theeuwes JW, Jansen Steur EN, de Vos RA (2000) Activated Microglial cells and complement factors are unrelated to cortical Lewy bodies. Acta Neuropathol.(Berl) 100:701-708
    Abstract: Inflammatory mechanisms have been demonstrated in Alzheimer's disease (AD) but their presence in other neurodegenerative disorders is not well documented. Complement factors and activated Microglia have been reported in the substantia nigra of Parkinson's disease (PD). In the present study we investigated the cingulate gyrus of 25 autopsied patients with clinically and neuropathologically well-documented PD, with or without dementia, for the presence of (activated) Microglial cells and their relation with Lewy body (LB)-bearing neurons. In addition, we studied the presence of complement factors in LBs. Of the 25 patient, 15 were clinically demented, fulfilling criteria for dementia with LBs (DLB); 7 also fulfilled CERAD morphological criteria for probable or definite Alzheimer type of dementia. Microglia clustering was seen around congophilic plaques with or without tau pathology. Microglial cells were not associated with LB-bearing neurons or noncongophilic plaques. The cortex of DLB patients without AD plaques did not show more Microglial cells than the cortex of non-demented controls. The number of Microglia was the lowest in young control patients who died immediately after trauma. Complement factor C3d was occasionally seen in diffusely ubiquinated neurons but late complement factors were not detected in these neurons. Double staining for complement and alpha-synuclein was negative, suggesting the absence of complement in LBs. In contrast, AD plaques in the same sections showed complement factors C3c, C3d, C1q and C5-9. In conclusion, we have found no evidence that inflammatory mechanism are involved in LB formation in cerebral cortex

75. Chang JY, Liu LZ (1999) Manganese potentiates nitric oxide production by Microglia. Brain Res.Mol.Brain Res. 68:22-28
    Abstract: Manganese toxicity has been associated with clinical symptoms of neurotoxicity which are similar to the symptoms observed in Parkinson's disease. Earlier reports indicated that reactive Microglia was present in the substantia nigra of patients with Parkinson's disease. Using N9 Microglial cells, the current study was designed to determine whether high levels of manganese were associated with Microglial activation. Results indicated that manganese significantly increased the bacterial lipopolysaccharide-induced nitric oxide production. This potent activity of manganese was not shared by other transition metals tested, including iron, cobalt, nickel, copper and zinc. Immunohistochemical staining and Western blot analysis indicated that manganese increased the cellular production of inducible nitric oxide synthase. Northern blot analysis indicated that manganese likely increased iNOS gene transcription since this agent increased the mRNA level of the inducible nitric oxide synthase. In contrast to other transition metals tested, manganese did not appear to be cytotoxic to Microglial cells. These results suggested that manganese could induce sustained production of neurotoxic nitric oxide by activated Microglial cells, which might cause detrimental consequences to surrounding neurons

76. Dobbs RJ, Charlett A, Purkiss AG, Dobbs SM, Weller C, Peterson DW (1999) Association of circulating TNF-alpha and IL-6 with ageing and Parkinsonism. Acta Neurol.Scand. 100:34-41
    Abstract: INTRODUCTION: We propose that the increase in TNF-alpha and IL-6 in the brain in idiopathic Parkinsonism is in response to a peripheral immune/ inflammatory process, so ubiquitous as to be responsible for the resemblance between ageing and Parkinsonism. METHODS: Circulating cytokine was measured in 78 subjects with idiopathic Parkinsonism and 140 without, aged 30 to 90 years, all obeying inclusion/exclusion criteria. RESULTS: Serum TNF-alpha increased (P<0.0001) by 1.37 (95% CI 0.75, 2.00)% x y(-1), IL-6 by 2.63 (1.75, 3.52) (P<0.0005). TNF-alpha appeared elevated in Parkinsonians whose postural and psychomotor responses were abnormal, being suppressed where they were normal: trends which contrasted with those in controls (P = 0.015 and 0.05, respectively). Parkinsonism appeared (P = 0.08) to have an effect on IL-6, equivalent to that of >10 years of ageing (28(-3, 69)%), but was not immediately related to between-subject differences in performance. CONCLUSION: Ageing and pathogenetic insult may be confounded, age being a progression, not a risk, factor

77. Hironishi M, Ueyama E, Senba E (1999) Systematic expression of immediate early genes and intensive astrocyte activation induced by intrastriatal ferrous iron injection. Brain Res. 828:145-153
    Abstract: The potential role(s) of transitional metals such as iron have been implicated in neurodegeneration through biochemical processes, particularly oxidative stress. We injected ferrous chloride (FeCl2) and ferric chloride (FeCl3) into the striatonigral system of Sprague-Dawley rats to investigate the biological and toxic effects of ferrous iron in the central nervous system. When FeCl2 was injected into the ventral midbrain, rats showed a characteristic behavior which indicated ipsilateral dopaminergic hyperactivity. FeCl2 injection into the striatum induced a dose-dependent damage, the activation of astrocytes and recruitment of macrophage/Microglia at the injected site. Interestingly, the activation of astrocytes was also observed in the anatomically remote areas such as the ipsilateral subthalamic nucleus and pars reticulata of the substantia nigra after 1 week. Expression of immediate early genes (IEGs; c-fos and NGFI-A) was observed in the cortex, thalamic nuclei, subthalamic nucleus, pars reticulata of the substantia nigra, lateral and medial geniculate bodies on the ipsilateral side from 3 to 15 h after FeCl2 injection. Pre-treatment with dimethyl sulfoxide, a hydroxyl radical scavenger, prevented FeCl2-induced expression of IEGs in the thalamic nuclei and geniculate bodies, but not in the cerebral cortex. On the other hand, the effects of FeCl3 were faint and limited on IEGs expression and tissue damage. These results suggest that ferrous iron affects the nervous system vigorously, possibly yielding free radicals such as hydroxyl radicals, and could be one of the important candidates for neurodegenerative diseases under the state in which acclimating systems for iron toxicity are disrupted

78. Hunot S, Dugas N, Faucheux B, Hartmann A, Tardieu M, Debre P, Agid Y, Dugas B, Hirsch EC (1999) FcepsilonRII/CD23 is expressed in Parkinson's disease and induces, in vitro, production of nitric oxide and tumor necrosis factor-alpha in glial cells. J.Neurosci. 19:3440-3447
    Abstract: Oxidative stress is thought to be involved in the mechanism of nerve cell death in Parkinson's disease (PD). Among several toxic oxidative species, nitric oxide (NO) has been proposed as a key element on the basis of the increased density of glial cells expressing inducible nitric oxide synthase (iNOS) in the substantia nigra (SN) of patients with PD. However, the mechanism of iNOS induction in the CNS is poorly understood, especially under pathological conditions. Because cytokines and FcepsilonRII/CD23 antigen have been implicated in the induction of iNOS in the immune system, we investigated their role in glial cells in vitro and in the SN of patients with PD and matched control subjects. We show that, in vitro, interferon-gamma (IFN-gamma) together with interleukin-1beta (Il-1beta) and tumor necrosis factor-alpha (TNF-alpha) can induce the expression of CD23 in glial cells. Ligation of CD23 with specific antibodies resulted in the induction of iNOS and the subsequent release of NO. The activation of CD23 also led to an upregulation of TNF-alpha production, which was dependent on NO release. In the SN of PD patients, a significant increase in the density of glial cells expressing TNF-alpha, Il-1beta, and IFN-gamma was observed. Furthermore, although CD23 was not detectable in the SN of control subjects, it was found in both astroglial and Microglial cells in Parkinsonian patients. Altogether, these data demonstrate the existence of a cytokine/CD23-dependent activation pathway of iNOS and of proinflammatory mediators in glial cells and their involvement in the pathophysiology of PD

79. Kurkowska-Jastrzebska I, Wronska A, Kohutnicka M, Czlonkowski A, Czlonkowska A (1999) MHC class II positive Microglia and lymphocytic infiltration are present in the substantia nigra and striatum in mouse model of Parkinson's disease. Acta Neurobiol.Exp.(Wars.) 59:1-8
    Abstract: We have studied MHC class II antigen expression and lymphocytic infiltration during dopaminergic neurone degeneration produced by intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropiridine (MPTP). Microglial activation was observed in the striatum and in the substantia nigra (SN) in this model. We noticed a marked increase of MHC class II antigen expression on Microglia and T-cell recruitment in these regions after MPTP treatment. B-lymphocytes were not observed. T-cell infiltration predominantly consisted of CD8+ cells at every time point but CD4+ cells were present too. More than a half of the observed lymphocytes showed strong staining of CD44 antigen. Our findings suggest a possible immune system involvement in the pathological process following MPTP intoxication

80. Liberatore GT, Jackson-Lewis V, Vukosavic S, Mandir AS, Vila M, McAuliffe WG, Dawson VL, Dawson TM, Przedborski S (1999) Inducible nitric oxide synthase stimulates dopaminergic neurodegeneration in the MPTP model of Parkinson disease. Nat.Med. 5:1403-1409
    Abstract: MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) damages dopaminergic neurons as seen in Parkinson disease. Here we show that after administration of MPTP to mice, there was a robust gliosis in the substantia nigra pars compacta associated with significant upregulation of inducible nitric oxide synthase (iNOS). These changes preceded or paralleled MPTP-induced dopaminergic neurodegeneration. We also show that mutant mice lacking the iNOS gene were significantly more resistant to MPTP than their wild-type littermates. This study demonstrates that iNOS is important in the MPTP neurotoxic process and indicates that inhibitors of iNOS may provide protective benefit in the treatment of Parkinson disease

81. Renkawek K, Stege GJ, Bosman GJ (1999) Dementia, gliosis and expression of the small heat shock proteins hsp27 and alpha B-crystallin in Parkinson's disease. Neuroreport 10:2273-2276
    Abstract: Cognitive impairment and dementia are common in the later stages of Parkinson's disease (PD). Neuropathological examination of demented PD (PDD) patients often reveals changes that are typical of Alzheimer's disease (AD). In AD, there is a massive reactive gliosis and increased expression of the small heat shock proteins (hsp) hsp27 and alpha B-crystallin. Since these proteins are characteristic for reactive astrocytes in AD, we investigated their expression in the brains of PDD patients. The results were compared with those obtained in the brains of non-demented PD patients. We found (1) no detectable expression of hsp in PD without dementia, and low expression in PD with mild dementia; (2) reactive gliosis and increased expression of hsp in the cortex of PDD brains; (3) a strong association between hsp immunoreactivity and the severity of the AD-specific changes, especially with the number of tangles in the hippocampus; (4) a distinct immunoreaction of alpha B-crystallin in Microglia in the substantia nigra and in the hippocampus in PDD. These results indicate that astrocytes react to the disease conditions in AD and in PDD in a similar way, namely by the increased expression of small heat shock proteins, and present additional evidence for the thesis that the pathology of the dementia in PD is related to that in AD

82. Torreilles F, Salman-Tabcheh S, Guerin M, Torreilles J (1999) Neurodegenerative disorders: the role of peroxynitrite. Brain Res.Brain Res.Rev. 30:153-163
    Abstract: Inflammatory reaction is thought to be an important contributor to neuronal damage in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and the Parkinsonism dementia complex of Guam. Among the toxic agents released in brain tissues by activated cells, we focus attention in this review on peroxynitrite, the product of the reaction between nitric oxide (NO) and superoxide. Peroxynitrite is a strong oxidizing and nitrating agent which can react with all classes of biomolecules. In the CNS it can be generated by Microglial cells activated by pro-inflammatory cytokines or beta-amyloid peptide (beta-A) and by neurons in three different situations: hyperactivity of glutamate neurotransmission, mitochondrial dysfunction and depletion of L-arginine or tetrahydrobiopterin. The first two situations correspond to cellular responses to an initial neuronal injury and the peroxynitrite formed only exacerbates the inflammatory process, whereas in the third situation the peroxynitrite generated directly contributes to the initiation of the neurodegenerative process

83. Willing AE, Sudberry JJ, Othberg AI, Saporta S, Poulos SG, Cameron DF, Freeman TB, Sanberg PR (1999) Sertoli cells decrease Microglial response and increase engraftment of human hNT neurons in the hemiParkinsonian rat striatum. Brain Res.Bull. 48:441-444
    Abstract: Sertoli cells (SCs) provide immune protection and nutritive support to the developing germ cells in the testis. Sertoli cells have also been shown to provide immune protection to islets transplanted outside the testes. In this study, the ability of these cells to diminish the infiltration/activation of Microglia into a neural graft implanted in the lesioned striatum of a hemiParkinsonian rat was investigated. Human neuron-like cells (hNT neurons) were implanted either alone or in combination with rat SCs. Three months later, the animals were sacrificed and immunohistochemistry was performed to determine the survival of the xenografted neurons as well as Microglial infiltration/activation. Cotransplantation of the SCs with the hNT neurons increased graft survival and was associated with an increase in graft size. Furthermore, there were fewer Microglia present in the grafted tissue of the cotransplantation groups. These results show that SCs retain their immunosuppressive ability even within the brain. As immune responses to grafted neural tissue within the central nervous system become better understood, this ability of the SCs to provide localized immunosuppression to the transplanted tissue may become more important. This is particularly true as the search for alternative sources of neural tissue to treat neurodegenerative diseases expands to encompass other species

84. Banati RB, Daniel SE, Blunt SB (1998) Glial pathology but absence of apoptotic nigral neurons in long-standing Parkinson's disease. Mov Disord. 13:221-227
    Abstract: The cause and mechanism of neuronal cell death in the substantia nigra of patients with Parkinson's disease (PD) are unknown. There is also controversy about whether the cell death results from a single event followed by cell loss consistent with aging or whether there is an ongoing pathologic process. Using postmortem tissue obtained from the Parkinson's Disease Society Brain Tissue Bank in London, we have sought to establish whether apoptosis, or more specifically DNA fragmentation of neurons, is a prominent feature of nigral pathology. In addition, we have studied Microglial activation in the substantia nigra as an indicator of ongoing pathology using the highly sensitive markers CR3/43 and EBM11. Reactive astrocytes have been assessed using immunostaining for glial fibrillary acidic protein (GFAP). Ten patients with pathologically proven PD were studied. In all cases, regardless of disease duration, severity, drug treatment, or age of the patient, there was no evidence of apoptosis in the substantia nigra as assessed by in situ end-labeling of DNA fragments using biotinylated dUTP and terminal deoxynucleotidyl transferase (TdT). In contrast, a case of multiple system atrophy (MSA) served as a positive control for the technique. In this case, positive DNA end-labeling could be found in neurons and non-neuronal cells in the brain stem. In the PD cases, there was, however, localized pathology in the substantia nigra as revealed by the CR3/ 43 and EBM11 markers for activated Microglia. This process seemed independent of disease duration and was florid even in patients with severe neuronal loss. It remains to be determined to what extent the activation of glial cells reflects progressive nigral pathology, and whether those factors which are classically associated with prominent apoptotic neuronal cell death in vivo, such as neurotrophic factor deprivation, are prime causes of nigral neuronal loss in PD. Future studies should focus on recent-onset PD or incidental Lewy body disease to further address these questions

85. Borlongan CV, Saporta S, Sanberg PR (1998) Intrastriatal transplantation of rat adrenal chromaffin cells seeded on microcarrier beads promote long-term functional recovery in hemiParkinsonian rats. Exp.Neurol. 151:203-214
    Abstract: Possible biologic treatments for Parkinson's disease, a disorder caused by the deterioration of dopaminergic neurons bridging the nigrostriatal system, have recently focused on fetal cell transplantation. Because of ethical and tissue availability issues concerning fetal cell transplantation, alternative cell sources are being developed. The adrenal medulla has been used as a cell transplant source because of the capacity of the cells to provide catecholamines and to transform into a neuronal phenotype. However, adrenal tissue transplants have shown limited success, primarily because of their lack of long-term viability. Recently, seeding adrenal chromaffin cells on microcarrier beads has been shown to enhance the cell viability following neural transplantation. In the present study, we further investigated whether transplantation of rat adrenal chromaffin cells seeded on microcarrier beads into the striatum of 6-hydroxydopamine-induced hemiParkinsonian rats would result in a sustained functional recovery. Behavioral tests using the apomorphine-induced rotational and elevated body swing tests up to 12 months posttransplantation revealed a significant behavioral recovery in animals that received adrenal chromaffin cells seeded on microcarrier beads compared to animals that received adrenal chromaffin cells alone, medium alone, or beads alone. Histological examination of tissue at 14 months posttransplantation revealed evidence of tyrosine hydroxylase-positive cells and an on-going glial response in animals transplanted with adrenal chromaffin cells seeded on microcarrier beads, in contrast to absence of such immunoreactive responses in the other groups. These findings support a facilitator role for microcarrier beads in transplantation of adrenal chromaffin cells or other cells that are easily rejected by the CNS

86. Chen S, Le WD, Xie WJ, Alexianu ME, Engelhardt JI, Siklos L, Appel SH (1998) Experimental destruction of substantia nigra initiated by Parkinson disease immunoglobulins. Arch.Neurol. 55:1075-1080
    Abstract: BACKGROUND: Increased levels of free radicals and oxidative stress may contribute to the pathogenesis of substantia nigra (SN) injury in Parkinson disease (PD), but the initiating etiologic factors remain undefined in most cases. OBJECTIVE: To determine the potential importance of immune mechanisms in triggering or amplifying neuronal injury, we assayed serum samples from patients with PD to determine the ability of IgG to initiate relatively specific SN injury in vivo. METHODS: IgG purified from the serum of 5 patients with PD and 10 disease control (DC) patients was injected into the right side of the SN in adult rats. Coronal sections were cut from the whole brain at the level of the stereotaxic injections, stained for tyrosine hydroxylase and with cresyl violet, and cellular profiles were counted in identical brain regions at the injection and contralateral sides. The ratio of cell profile counts of the corresponding injected and uninjected regions was used as an internal standard. RESULTS: Four weeks following injection of IgG, a 50% decrease in tyrosine hydroxylase-positive cellular profiles was noted on the injected sides compared with the contralateral sides of the same animals. Similarly, applied DC IgG caused only an 18% decrease. Cresyl violet staining revealed a 35% decrease in neuronal profiles of PD IgG injected into the SN pars compacta compared with the contralateral uninjected side, whereas DC IgG caused a minimal 10% decrease. Even at 4 weeks after the PD IgG injections, perivascular inflammation and significant Microglial infiltration were present near injured SN pars compacta neurons. No cytotoxic effects of PD IgG were noted in choline acetyltransferase-positive neurons after stereotaxic injections into the medial septal region. Absorption of PD IgG with mesencephalic membranes and protein A agarose gel beads removed cytotoxicity, while absorption with liver membranes did not change the cytotoxicity. CONCLUSIONS: Our data suggest that PD IgG can initiate a relatively specific inflammatory destruction of SN pars compacta neurons in vivo and demonstrate the potential relevance of immune mechanisms in PD

87. Kohutnicka M, Lewandowska E, Kurkowska-Jastrzebska I, Czlonkowski A, Czlonkowska A (1998) Microglial and astrocytic involvement in a murine model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Immunopharmacology 39:167-180
    Abstract: We have studied the reaction of glial cells in mice treated with an intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a selective neurotoxin of dopaminergic nigrostriatal neurons. Signs of injury to the dopaminergic neurons started on the 1st day after MPTP administration and progressed up to the end of the observation time (21st day). A transient Microglial reaction was demonstrated from the 1st until the 14th day in the substantia nigra (SN) and striatum. The cells showed an increase in number and changes in morphology. At the ultrastructural level, signs of phagocytosis and features indicating the secretion of biologically active substances were observed. Astrocytosis followed the Microglial reaction by one day and was noticed until the end of the observation time. Interleukin-6 immunoreactivity was observed within Microglia and astrocytes in the SN on days 2 and 3. There were no signs of depletion of dopaminergic cells or glial activation after the administration of MPTP simultaneously with pargyline, an inhibitor of monoamine oxidase-B that prevents MPTP neurotoxicity. Our study indicates that Microglia and astrocytes are involved in the pathological process in the nigrostriatal system following MPTP administration. MPTP alone is not responsible for glial cell activation but its metabolite MPP+ and/or agents released by injured neurons may participate in this process

88. McGeer EG, McGeer PL (1998) The importance of inflammatory mechanisms in Alzheimer disease. Exp.Gerontol. 33:371-378
    Abstract: Lesions in such chronic neurodegenerative disorders as Alzheimer disease (AD), Parkinson disease, the Parkinsonism dementia complex of Guam, and amyotrophic lateral sclerosis have associated with them a variety of proteins known to be involved in inflammatory processes. This is particularly true of AD, where inflammatory reactions are thought to be important contributors to the neuronal loss. Proteins present include complement proteins, complement inhibitors, acute phase reactants, inflammatory cytokines, proteases, and protease inhibitors. Studies of cultured human astrocytes and Microglia, obtained from postmortem brain, have established that nearly all of these proteins are produced by one or another of these cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid and extracellular tangles apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products. Such products include the membrane attack complex, oxygen free radicals, and excess glutamate. Twenty epidemiological studies that have been published to date indicate that populations taking antiinflammatory drugs have a significantly reduced prevalence of AD or a slower mental decline. One small clinical trial with indomethacin showed arrest of the disease over a six-month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of AD and possibly other neurodegenerative disorders

89. McGeer PL, McGeer EG (1998) Mechanisms of cell death in Alzheimer disease--immunopathology. J.Neural Transm.Suppl 54:159-166
    Abstract: Lesions in such chronic neurodegenerative disorders as Alzheimer disease, Parkinson disease, the Parkinsonism dementia complex of Guam and amyotrophic lateral sclerosis have associated with them a variety of proteins known to be involved in inflammatory processes. This is particularly true of Alzheimer disease where inflammatory reactions are thought to be important contributors to the neuronal loss. They include complement proteins, complement inhibitors, acute phase reactants, inflammatory cytokines, proteases and protease inhibitors. Studies of cultured human astrocytes and Microglia, obtained from postmortem brain, have established that nearly all of these proteins are produced by one or another of these cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid and extracellular tangles apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products. Such products include the membrane attack complex, oxygen free radicals and excess glutamate. Twenty epidemiological studies that have been published to data indicate that populations taking antiinflammatory drugs have a significantly reduced prevalence of Alzheimer disease or a slower mental decline. One small clinical trial with indomethacin showed arrest of the disease over a 6 month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of Alzheimer disease and possibly other neurodegenerative disorders

90. McGeer PL, McGeer EG (1998) Glial cell reactions in neurodegenerative diseases: pathophysiology and therapeutic interventions. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S1-S6
    Abstract: A variety of proteins known to be involved in inflammatory processes are associated with lesions in chronic neurodegenerative disorders such as Alzheimer disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). This is particularly true of AD, in which inflammatory reactions are believed to be important contributors to the neuronal loss. Inflammatory proteins associated with AD include complement proteins, complement inhibitors, acute-phase reactants, inflammatory cytokines, proteases, and protease inhibitors. Studies of cultured human astrocytes and Microglia obtained from postmortem brain have established that almost all of these proteins are produced by one or the other of these two cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid, extracellular tangles, or Lewy bodies apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products such as the membrane attack complex, oxygen free radicals, and excess glutamate. A number of epidemiologic studies indicate that populations taking anti-inflammatory drugs have a sharply reduced prevalence of AD. One small clinical trial with indomethacin showed arrest of the disease over a 6-month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of AD and possibly other neurodegenerative disorders

91. Nakajima K, Kohsaka S (1998) [Microglia: function in the pathological state]. No To Shinkei 50:5-16

92. Schwarz SC, Schwarz J, Sautter J, Oertel WH (1998) Effects of macrophage migration inhibitory factor and macrophage migration stimulatory factor on function and survival of foetal dopaminergic grafts in the 6-hydroxydopamine rat model of Parkinson's disease. Exp.Brain Res. 120:95-103
    Abstract: Activated Microglia play an important role in the rejection of intracerebral grafts and the degeneration of axotomized neurones. We studied the effect of macrophage migration stimulatory factor (MSF) or macrophage migration inhibitory factor (MIF) on allogeneic foetal mesencephalic dopaminergic grafts transplanted into the striatum of 6-hydroxydopamine-lesioned rats. Rotation testing revealed a significant compensation of lesion-induced motor asymmetry 3 weeks post-grafting in animals treated with MIF and vehicle-treated controls compared with pre-graft values (Student's t-test, P < or = 0.005) and MSF-treated animals (ANOVA, post hoc Fisher PLSD test, P < or = 0.05). The MSF group showed no significant compensation. Graft recipients with MIF application (1452.06 +/- 164.32 tyrosine hydroxylase-positive ventral mesencephalic cells) and controls (1753.21 +/- 165.51 tyrosine hydroxylase-positive neurones) displayed good graft survival. Animals with MSF application showed a significant reduction of tyrosine hydroxylase-positive grafted cells (MSF 570.36 +/- 209.49 cells) and graft volumes compared with the MIF and the control group (ANOVA, post hoc Fisher PLSD test, P < or = 0.05). The proportional area of Microglia was significantly reduced in MIF animals compared with control animals (ANOVA, post hoc Fisher PLSD test, P < or = 0.001). Activated Microglia and macrophages were reduced by half in the MIF-treated group compared with MSF animals and controls. We conclude that intrastriatal injections of MSF result in impaired function and survival of allogeneic ventral mesencephalon (VM) grafts 3 weeks after transplantation. MIF can reduce the number of Microglia and macrophages in allogeneic foetal VM grafts. A reduction of Microglia via MIF application did not enhance graft function and survival

93. Schwarz SC, Seufferlein T, Liptay S, Schmid RM, Kasischke K, Foster OJ, Daniel S, Schwarz J (1998) Microglial activation in multiple system atrophy: a potential role for NF-kappaB/rel proteins. Neuroreport 9:3029-3032
    Abstract: Microglial activation is a prominent feature of affected brain areas in multiple system atrophy. Microglia express proinflammatory peptides, which may be a result of activation of nuclear factor-KB. We investigated the nuclear presence of RelA, the 65 kDa subunit of the NF-KB/RelA family in striatum and brain stem of patients with multiple system atrophy. Affected brain areas of patients with multiple system atrophy showed a marked immunoreactivity for nuclear Rel A p65, which was almost exclusively localized in activated Microglia. Interestingly nuclear translocation of Rel A was not detected in striatal tissue of controls and Parkinson disease patients. Thus, NF-kappaB/Rel A complexes may play a role in mediating Microglial activation in multiple system atrophy

94. Walker DG, Beach TG, Xu R, Lile J, Beck KD, McGeer EG, McGeer PL (1998) Expression of the proto-oncogene Ret, a component of the GDNF receptor complex, persists in human substantia nigra neurons in Parkinson's disease. Brain Res. 792:207-217
    Abstract: The proto-oncogene Ret, a membrane-associated receptor protein tyrosine kinase, has recently been shown to be a component of the glial cell line-derived neurotrophic factor (GDNF) receptor complex. GDNF has potent dopaminergic neurotrophic properties and has been suggested as a treatment for Parkinson's disease (PD). In this study, tissue sections of human substantia nigra (SN) from normal and PD cases were examined to determine the pattern of Ret expression in this region, and whether there was continued Ret expression in surviving dopaminergic neurons in PD cases. Using a polyclonal antibody to the amino terminal of Ret, immunoreactivity was localized in the SN to dopaminergic neurons. The antibody predominantly identified punctate deposits within cells. A similar pattern of immunoreactivity was observed in rat and monkey SN neurons. In neurologically normal cases, immunoreactivity was detected in many of the SN neurons. In all the PD cases studied, continued expression of Ret was observed in many of the surviving dopaminergic neurons. In certain cases, it was also detected on cells with the morphology of Microglia. Ret expression by Microglia was confirmed by immunoblot analysis on the human THP-1 macrophage type cell line. However, these cells did not express the mRNA for GDNFRalpha, the other component of the GDNF receptor complex

95. Bertrand E, Lechowicz W, Szpak GM, Dymecki J (1997) Qualitative and quantitative analysis of locus coeruleus neurons in Parkinson's disease. Folia Neuropathol. 35:80-86
    Abstract: The analysis of qualitative changes in the locus coeruleus (LC) was performed on brains from 21 cases of Parkinson's disease. Eleven cases were selected for quantitative analysis of the loss of LC noradrenergic pigmented neurons. The qualitative studies revealed uneven dissemination of the noradrenergic cells loss of overall structure of the LC. Few preserved neurons showed degenerative changes. Extracellular neuromelanine granules, traces of dying neurons, were also observed. A weak astro- and Microglia proliferation corresponded with neuronal loss. Lewy bodies were found in the LC in all cases. The quantitative analysis revealed that the average loss of adrenergic neurons in the LC accounts for about 70% in relation to the control group. The degenerative changes were observed in the whole LC, but they were most intensive in its caudal and next in the middle segment. The results suggest also that the degenerative process began in the middle segment and then it spread towards caudal segment of the LC as the stages of disease advanced

96. Deacon T, Schumacher J, Dinsmore J, Thomas C, Palmer P, Kott S, Edge A, Penney D, Kassissieh S, Dempsey P, Isacson O (1997) Histological evidence of fetal pig neural cell survival after transplantation into a patient with Parkinson's disease. Nat.Med. 3:350-353
    Abstract: The movement disorder in Parkinson's disease results from the selective degeneration of a small group of dopaminergic neurons in the substantia nigra pars compacta region of the brain. A number of exploratory studies using human fetal tissue allografts have suggested that transplantation of dopaminergic neurons may become an effective treatment for patients with Parkinson's disease and the difficulty in obtaining human fetal tissue has generated interest in finding corresponding non-human donor cells. Here we report a post-mortem histological analysis of fetal pig neural cells that were placed unilaterally into the caudate-putamen brain region of a patient suffering from Parkinson's disease. Long-term (over seven months) graft survival was found and the presence of pig dopaminergic neurons and other pig neural and glial cells is documented. Pig neurons extended axons from the graft sites into the host brain. Furthermore, other graft derived cells were observed several millimeters from the implantation sites. Markers for human Microglia and T-cells showed only low reactivity in direct proximity to the grafts. This is the first documentation of neural xenograft survival in the human brain and of appropriate growth of non-human dopaminergic neurons for a potential therapeutic response in Parkinson's disease

97. Kawaguchi N, Yamada T, Yoshiyama Y (1997) [Expression of interferon-alpha mRNA in human brain tissues]. No To Shinkei 49:69-73
    Abstract: The localization of mRNA of interferon-alpha (IFNA21) was examined in human brain tissues from neurologically normal, Parkinson's and Alzheimer's disease (AD) cases, using an in situ hybridization method. In all cases, signals for the mRNA of IFNA21 were detected in the white matter Microglial cells. In AD brains, a few neurons in the parietal lobe were intensely labeled. These results suggest that one type of IFN-alpha protein is constitutively expressed in white matter Microglial cells, and that expression of IFN-alpha in neuronal cells may play some role in AD pathology

98. Kordower JH, Styren S, Clarke M, DeKosky ST, Olanow CW, Freeman TB (1997) Fetal grafting for Parkinson's disease: expression of immune markers in two patients with functional fetal nigral implants. Cell Transplant. 6:213-219
    Abstract: In a number of centers throughout the world, fetal nigral transplantation is being performed for the treatment of Parkinson's disease (PD). Clinical results have been inconsistent. One parameter that differs among transplant studies is the degree and manner by which patients are immunosuppressed following transplantation. Indeed, the role of the immune system following fetal grafting in humans is not well understood. Recently, two patients from our open label trial that received fetal nigral implants have come to autopsy. These patients were immunosuppressed with cyclosporin for 6 mo posttransplantation and survived for a total of 18 mo postgrafting. Robust survival of grafted dopamine-containing cells was observed in both cases. Immunostaining for HLA-DR revealed a dense collection of cells within grafts from both cases. HLA-DR staining was rarely observed within the host including nongrafted regions of the striatum. A more detailed analysis of immune markers was performed in Case 2. Numerous pan macrophages, T-cells, and B-cells were observed within graft sites located in the postcommissural putamen. In contrast, staining for these immune cells was not observed within the ungrafted anterior putamen. These findings suggest that even in healthy appearing functional nigral implants, grafts are invaded by host immune cells that could compromise their long-term viability and function. Alternatively, immune cells are known to secrete trophic factors, which may ultimately favor graft survival and function. Further work is needed to understand the role of the immune system in fetal grafting

99. Kosel S, Egensperger R, von Eitzen U, Mehraein P, Graeber MB (1997) On the question of apoptosis in the Parkinsonian substantia nigra. Acta Neuropathol.(Berl) 93:105-108
    Abstract: Apoptosis has been postulated as a mechanism of nerve cell death in Parkinson's disease. In the present study, the substantia nigra of 22 neuropathologically confirmed Parkinson cases and 8 control brains was studied using the in situ end-labeling (TUNEL) method. About 50% of Parkinsonian brains showed a small number of TUNEL-positive glial cells in the substantia nigra, whereas no neurons showed convincing TUNEL positivity or any morphological signs of apoptosis. No correlation was observed between the number of TUNEL-positive glial cells and Microglial activation. Our results fail to demonstrate apoptosis as a mechanism of cell death in Parkinson's disease

100. McGeer EG, McGeer PL (1997) The role of the immune system in neurodegenerative disorders. Mov Disord. 12:855-858

101. McGeer PL, Schwab C, McGeer EG, Haddock RL, Steele JC (1997) Familial nature and continuing morbidity of the amyotrophic lateral sclerosis-Parkinsonism dementia complex of Guam. Neurology 49:400-409
     Abstract: Chamorros suffer from two neurologic syndromes known as ALS and the Parkinsonism-dementia complex (PDC) of Guam. We report mortality figures for these syndromes during 1991 to 1995 and compare them with those at 5-year intervals dating back to 1951. In contrast to predictions of disease disappearance, both syndromes remain prevalent. However, age of onset and age at death have increased for both syndromes, suggesting that shifting environmental factors are causing disease postponement. We also report the clinical, familial, neuropathologic, and immunohistochemical findings on a consecutive autopsy series of Guamanian Chamorro cases. Twelve cases were diagnosed as PDC, known locally as "bodig," and three as ALS, known locally as "lytico." All but three of these fifteen patients had a pronounced family history of similar illness. Eight of twelve boding patients had siblings who were also affected with bodig; two of three lytico cases had siblings afflicted with lytico. The family histories are compatible with genetic transmission of each syndrome. The neuropathology of bodig is characterized by severe and widespread neurofibrillary tangle (NFT) development. NFTs are surrounded by reactive Microglia and reactive astrocytes, and complement proteins and other molecules connected with inflammation are associated with them. Similar inflammatory responses also occur in Alzheimer's disease (AD) but have been largely attributed to the presence of senile plaques. These data indicate that tangles, as well as plaques, generate inflammatory reactions that such reactions may exacerbate the fundamental pathology in bodig as well as in AD

102. Pearce RK, Owen A, Daniel S, Jenner P, Marsden CD (1997) Alterations in the distribution of glutathione in the substantia nigra in Parkinson's disease. J.Neural Transm. 104:661-677
     Abstract: Depletion of reduced glutathione occurs in the substantia nigra in Parkinson's disease and in incidental Lewy body disease (presymptomatic Parkinson's disease) which may implicate oxidative stress in the neurodegenerative process. In this study mercury orange fluorescent staining and immunostaining with an antibody to reduced glutathione have been used to determine the distribution of reduced glutathione in the substantia nigra in Parkinson's disease compared with normal individuals. Mercury orange staining showed moderate background levels of fluorescence in the neuropil in both control and Parkinson's disease substantia nigra and localised reduced glutathione to the somata of melanized nigral neurons and glial elements of the neuropil. Neuronal nuclei revealed a relative lack of fluorescence after mercury orange staining. There was a significant depletion of reduced glutathione in surviving neurons in Parkinson's disease compared to nerve cell populations in control tissue. Mercury orange fluorescence indicated a high concentration of reduced glutathione in a subpopulation of non-neuronal cells, most likely astrocytes or Microglia. Immunohistochemical examination of nigral tissue from the same Parkinson's disease and control patients with an antibody to glutathione showed staining in neuronal perikarya and axonodendritic processes of melanized nigral neurons which was generally most intense in control neurons. Moderately intense staining of the background neuropil, most prominent in control nigras, and staining of capillary walls was also detected. Intense staining was seen in cells with the morphological features of glial cells in both control and PD nigra. These data show a significant presence of reduced glutathione in the cell bodies and axons of nigral neurons. They are in agreement with biochemical studies showing depletion of reduced glutathione in substantia nigra in Parkinson's disease, and indicate a significant loss of neuronal reduced glutathione in surviving nigral neurons in Parkinson's disease

103. Pratt BM, McPherson JM (1997) TGF-beta in the central nervous system: potential roles in ischemic injury and neurodegenerative diseases. Cytokine Growth Factor Rev. 8:267-292
     Abstract: The Transforming Growth Factor-betas (TGF-beta) are a group of multifunctional proteins whose cellular sites of production and action are widely distributed throughout the body, including the central nervous system (CNS). Within the CNS, various isoforms of TGF-beta are produced by both glial and neural cells. When evaluated in either cell culture or in vivo models, the various isoforms of TGF-beta have been shown to have potent effects on the proliferation, function, or survival of both neurons and all three glial cell types, astrocytes, Microglia and oligodendrocytes. TGF-beta has also been shown to play a role in several forms of acute CNS pathology including ischemia, excitotoxicity and several forms of neurodegenerative diseases including multiple sclerosis, Parkinson's disease, AIDS dementia and Alzheimer's disease

104. Ruberg M, Brugg B, Prigent A, Hirsch E, Brice A, Agid Y (1997) Is differential regulation of mitochondrial transcripts in Parkinson's disease related to apoptosis? J.Neurochem. 68:2098-2110
     Abstract: A cDNA library of substantia nigra pars compacta from a patient with Parkinson's disease (PD) was differentially screened with probes of normal and Parkinsonian substantia nigra enriched in neuronal transcripts. Fifty-eight clones were isolated; 39 were subunits of mitochondrial respiratory complexes I and IV. Parallel screening of a cDNA library derived from normal substantia nigra confirmed differential representation of the transcripts in the substantia nigra pars compacta. In situ hybridization in postmortem brain from Parkinsonian and control subjects, with representative complex I and complex IV probes, showed increased labeling, at the cellular level, of the complex I subunit ND1 in neurons of the lateral substantia nigra, where cell death is greatest in PD, but decreased labeling in the medial substantia nigra where fewer cells die. Expression of a complex IV subunit, COXI, increased, however, in both parts of the structure. Increased expression of ND1 and COXI was also observed in nerve growth factor-differentiated PC12 cells undergoing apoptosis induced by tumor necrosis factor-alpha, suggesting that the differential regulation of certain mitochondrial mRNAs may be associated with this form of cell death. This in vitro model of apoptosis is potentially relevant to the death of dopaminergic neurons in PD, because these cells express the tumor necrosis factor-alpha receptor, and neighboring Microglial cells in patients synthesize the cytokine

105. Ruberg M, France-Lanord V, Brugg B, Lambeng N, Michel PP, Anglade P, Hunot S, Damier P, Faucheux B, Hirsch E, Agid Y (1997) [Neuronal death caused by apoptosis in Parkinson disease]. Rev.Neurol.(Paris) 153:499-508
     Abstract: The identity of the neuronal populations (dopaminergic, noradrenergic, serotoninergic, cholinergic) that die in Parkinson's disease is well established. The cause of this degeneration, and the mechanism by which it takes place is still unknown, although there is data, at least for the dopaminergic neurons, suggesting that oxidative stress might play a role. In addition, recent ultrastructural studies of dopaminergic neurons in patients with Parkinson's disease have shown that these neurons die by apoptosis, and immunocytochemical studies have shown that the cytokine TNF-alpha, observed in Microglial cells in the substantia nigra of patients post-mortem, might play a role, as might the transcription factor NF-kappa B, which is translocated into the nucleus of dopaminergic neurons in patients, a sign of its activation. We have developed an in vitro model of dopaminergic cell death that accounts for these observations. In both differentiated PC12 cells and primary cultures of mesencephalic neurons, we have shown that when the sphingomyelin-dependent signaling pathway is activated, these cells die by apoptosis, preceded by the production of superoxide radicals in the mitochondria and the nuclear translocation of NF-kappa B. TNF-alpha is known to induce all three such events: apoptosis, activation of the sphingomyelin pathway, free radical production. Our results suggest that the superoxide radicals are used as signalling molecules within the sphingomyelin pathway. These observations may help to explain the origin of the evidence, in postmortem brain from Parkinsonian patients, for oxidative stress, hypothesized to be an etiological factor in this disease

106. Tanaka M (1997) [Oxidative stress and the brain]. Nippon Ronen Igakkai Zasshi 34:706-710
     Abstract: Although the cause of Parkinson's disease is unknown, oxidative stress has been implicated in its pathogenesis. This theory postulates that normal metabolic processes in the nigrostriatal dopaminergic system may lead to loss of neurons, and that iron-dependent membrane lipid peroxidation may play an important role in the neuronal death. Recent research concerning iron-dependent lipid peroxidation is presented. First, catechols (including dopa and dopamine) and iron form strong oxidizing complexes and induce lipid peroxidation (LPO) in phospholipid liposomes. Active oxygen species including superoxide, hydrogen peroxide, hydroxyl radical and singlet oxygen, do not participate in this LPO, which is inhibited by an excess of dopa (dopamine). Cultured neurons and the substantia nigra are vulnerable to LPO. Second, synthetic melanin prepared by the autooxidation of catechols promotes LPO in the presence of iron. The effects of scavenging agents indicate that this LPO is mediated by superoxide, but not by other oxygen free radicals. Neuronal cell cultures are destroyed by this LPO. Third, catechols and superoxide produced by Microglia cause the release of iron from ferritin. Microglia stimulated by phorbol myristate acetate produce superoxide and cause the release of iron from ferritin. Catechols also induce mobilization of ferritin iron. The released iron (i.e. loosely-bound iron) is available to iron-dependent LPO. These data suggest that the biochemical and morphological characteristics of the substantia nigra, which are concomitant with its functional role, provoke iron-dependent lipid peroxidation. It is essential to elucidate how iron bound loosely to low molecules comes into contact with catechols, neuromelanin and superoxide. Drugs that chelate iron site-specifically or modulate the Microglial function may bring about some favorable changes in the disease process

107. Tompkins MM, Basgall EJ, Zamrini E, Hill WD (1997) Apoptotic-like changes in Lewy-body-associated disorders and normal aging in substantia nigral neurons. Am.J.Pathol. 150:119-131
     Abstract: In Parkinson's disease and other Lewy-body-associated disorders, the substantia nigra pars compacta undergoes degeneration, but the mechanism of cell death has not been previously described. The substantia nigra of normal and Alzheimer's disease cases were compared with substantia nigra from patients with Lewy-body-associated disorders (Parkinson's disease, concomitant Alzheimer's/Parkinson's disease, and diffuse Lewy body disease) using in situ end labeling to detect fragmented DNA. In situ end-labeled neurons demonstrated changes resembling apoptosis: nuclear condensation, chromatin fragmentation, and formation of apoptotic-like bodies. Ultrastructural analysis confirmed nuclear condensation and formation of apoptotic-like bodies. Apoptotic-like changes were seen in the substantia nigra of both normal and diseased cases; concomitant Alzheimer's/Parkinson's disease and diffuse Lewy body disease cases had significantly higher amounts of apoptotic-like changes than normal controls or Alzheimer patients. The finding of neuronal death by apoptosis may have relevance for the development of new treatment strategies for Parkinson's disease and related disorders

108. Czlonkowska A, Kohutnicka M, Kurkowska-Jastrzebska I, Czlonkowski A (1996) Microglial reaction in MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) induced Parkinson's disease mice model. Neurodegeneration. 5:137-143
     Abstract: We studied the Microglial reaction in mice using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced model for Parkinson's disease (PD). Microglial cells were identified by means of the Griffonia simplicifolia lectin (GSA-I-B4). Dopaminergic neurons were marked by tyrosine hydroxylase antibodies. Microglial activation was demonstrated by an increase in cellular number and changes of morphology (increased lectin staining, larger cell bodies and thicker processes) were seen in the substantia nigra from the 1st to the 14th day and in the striatum from the 1st to the 4th day after intoxication. Depletion of dopaminergic neurons was most pronounced 7 and 14 days following the treatment. The results suggest that Microglial activation may be involved in the sequence of pathological changes that lead to dopaminergic neuronal damage after MPTP intoxication

109. Goto K, Mochizuki H, Imai H, Akiyama H, Mizuno Y (1996) An immuno-histochemical study of ferritin in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced hemiParkinsonian monkeys. Brain Res. 724:125-128
     Abstract: Iron is increased in the substantia nigra of patients with Parkinson's disease, but the mechanism of its accumulation is unknown. We report the distribution of ferritin in the basal ganglia of hemiParkinsonian monkeys made by MPTP. We stereotactically injected MPTP unilaterally into the caudate nucleus of four monkeys, and the substantia nigra and the basal ganglia regions were stained for L-ferritin by an immunohistochemical method. The ferritin immuno-staining was most intense in the pallidum and the pars reticulata of the substantia nigra on both injected and non-injected sides. No significant difference was noted in the immunostaining for ferritin in the pars compacta of the substantia nigra between the injected and the non-injected side. Iron was increased in the pars compacta of the substantia nigra of this hemiParkinsonian monkeys in our previous study. Normal ferritin immunostaining on the injected side would indicate that iron accumulation is not related to altered metabolism of L-ferritin in this model

110. Sanberg PR, Borlongan CV, Saporta S, Cameron DF (1996) Testis-derived Sertoli cells survive and provide localized immunoprotection for xenografts in rat brain. Nat.Biotechnol. 14:1692-1695
     Abstract: Transplantation of neural tissue into the mammalian central nervous system has become an alternative treatment for neurodegenerative disorders such as Parkinson's disease. Logistical and ethical problems in the clinical use of human fetal neural grafts as a source of dopamine for Parkinson's disease patients has hastened a search for successful ways to use animal dopaminergic cells for human transplantation. The present study demonstrates that transplanted testis-derived Sertoli cells into adult rat brains survive. Furthermore, when cotransplanted with bovine adrenal chromaffin cells (xenograft), Sertoli cells produce localized immunoprotection, suppress Microglial response and allow the bovine cells to survive in the rat brain without continuous systemic immunosuppressive drugs. These novel features support Sertoli cells as a viable graft source for facilitating the use of xenotransplantation for Parkinson's disease and suggest their use as facilitators, (i.e., localized immunosuppression) for cell transplantation in general

111. Schwab C, Steele JC, McGeer PL (1996) Neurofibrillary tangles of Guam Parkinson-dementia are associated with reactive Microglia and complement proteins. Brain Res. 707:196-205
     Abstract: Guamanian Parkinsonism-dementia, locally described as bodig, is characterized by the widespread appearance of neurofibrillary tangles in cortical and subcortical areas. These tangles have similar regional distribution and immunohistochemical profile to those found in Alzheimer disease (AD). We studied the immunohistochemical staining of these tangles, as well as those of AD, using antibodies to complement proteins and related molecules. In bodig, as in AD, extracellular tangles were intensely decorated with antibodies to C1q, C4d and C3d, but not fraction Bb of factor B, properidin or immunoglobulins. This is evidence that the classical, but not the alternative complement pathway is activated on extracellular tangles and that the activation is independent of antibodies. Immunohistochemical staining for amyloid P, an in vitro activator of complement, was remarkably similar to that for the C1q, C4d and C3d in both bodig and AD. This was not the case for beta-amyloid protein (BAP), another in vitro complement activator. Positive staining was observed in only a minority of extracellular tangles in bodig and was only rarely observed in those of AD. BAP would therefore not appear to be a candidate for activating complement on extracellular neurofibrillary tangles. Reactive Microglia and reactive astrocytes were closely associated with complement positive extracellular neurofibrillary tangles, indicating an inflammatory response similar to that seen in AD

112. Schwarz J, Weis S, Kraft E, Tatsch K, Bandmann O, Mehraein P, Vogl T, Oertel WH (1996) Signal changes on MRI and increases in reactive microgliosis, astrogliosis, and iron in the putamen of two patients with multiple system atrophy. J.Neurol.Neurosurg.Psychiatry 60:98-101
     Abstract: A correlation of clinical, MRI, and neuropathological data is reported in two patients with multiple system atrophy (MSA). On MRI, patient 1 showed striatal atrophy, reduction of T2 relaxation times within most of the putamen, and a band of hyperintense signal changes in the lateral putamen. In patient 2, MRI disclosed only shortening of the T2 signal in the putamen. Immunohistochemistry showed pronounced reactive microgliosis and astrogliosis in the affected brain regions. In patient 1, the area with the most pronounced microgliosis and astrogliosis most likely correlated with the area of hyperintense signal changes on MRI. This area also contained the highest amount of ferric iron, which was increased in the putamen of patient 1 but not patient 2. It is unlikely that the hypointense signal changes in the putamen are due to an increase of iron alone. Reactive Microglial and astroglial cells may play a part in the pathogenesis of MSA

113. Schwarz SC, Kupsch AR, Banati R, Oertel WH (1996) Cellular immune reactions in brain transplantation: effects of graft pooling and immunosuppression in the 6-hydroxydopamine rat model of Parkinson's disease. Glia 17:103-120
     Abstract: We used high immunogenic mouse and low immunogenic rat brain transplants to investigate the effect of pooling of tissue with immunogenetic disparity on cellular immune reactions. Foetal xenogenic mouse striatum and allogenic rat substantia nigra were implanted into i) the 6-hydroxydopamine lesioned striatum of outbred female Sprague-Dawley rats as a pooled cell suspension, or into ii) the unlesioned and lesioned striata as non-pooled separate deposits, with or without immunosuppressive treatment with cyclosporin A (Cy A). In control animals, iii) mouse striatum was replaced by rat striatum, and iv) sham grafts with and without immunosuppression. Six weeks post grafting, brains were semiquantitatively processed using immunocytochemical markers for Microglia, astrocytes, T-helper cells, and macrophages, major histocompatibility class (MHC) I and II expression. The total amount of immunoreactivity (PA) for Microglial cells and astrocytes was pronounced and the PA for T-helper cells and macrophages was doubled in recipients of pooled rat and mouse cografts compared to non-pooled deposits, indicating ongoing immune reactions with participation of glial cells. MHC I expression was significantly increased in pooled xeno- and allogenic cografts with and without immunosuppression compared to allogenic controls. Expression of MHC II was significantly increased in pooled cografts without immunosuppression. In recipients of separate, non-pooled heteroimmunogenic cotransplants, MHC I and II expression was significantly increased in xenogenic deposits with and without immunosuppression. MHC II was as well significantly increased in allogenic deposits without immunosuppression. Immunosuppressed animals with non-pooled allogenic mouse cografts showed low levels of cellular immune parameters. In conclusion non-pooled heteroimmunogenic grafts lead to less pronounced immune reactions compared to pooled grafts and immunosuppressive treatment with Cy A has a beneficial effect on acute transplant-associated immune parameters

114. Shergill JK, Cammack R, Cooper CE, Cooper JM, Mann VM, Schapira AH (1996) Detection of nitrosyl complexes in human substantia nigra, in relation to Parkinson's disease. Biochem.Biophys.Res.Commun. 228:298-305
     Abstract: Idiopathic Parkinson's disease (PD) involves a documentable decline in the activity of mitochondrial complex I in substantia nigra (1-3). We have EPR spectroscopy to investigate complex I in human substantia nigra and globus pallidus. EPR signals characteristic of the iron-sulfur centers of complexes I and II were observed with globus pallidus, with no significant difference between control and PD. These complex 1 signals could not be clearly observed in substantia nigra. Instead, nitric oxide (NO.) radicals in PD nigra were detected at g approximately 2.08, 1.98 due to [haem-NO] formation. Although an EPR signal indicative of haem-NO was observed with control nigra, it lacked the distinctive g approximately 1.98 trough observed with PD nigra. As PD is associated with a reactive gliosis, the difference in the haem-NO EPR signal, between control and PD nigra, may result from cytotoxic NO. generated by Microglia in PD substantia nigra

115. Unsicker K, Suter-Crazzalora C, Krieglstein K (1996) Growth factor function in the development and maintenance of midbrain dopaminergic neurons: concepts, facts and prospects for TGF-beta. Ciba Found.Symp. 196:70-80
     Abstract: Dopaminergic neurons of the nigrostriatal system are important in the control of motor performance and degenerate in Parkinson's disease. Therefore, in order to design novel strategies for the treatment of Parkinson's disease, it is important for us to understand their development, function, trophic factor requirements, plasticity and susceptibility to toxic influences. A large and still increasing number of growth factors have been implicated in the regulation of the survival and differentiation of dopaminergic neurons. These factors may also protect against a variety of toxic influences. On the basis of their localization, putative sources and mechanisms of actions, such growth factors fall into several categories: (i) local factors within the midbrain influencing proliferation, transmitter phenotype, migration, positioning and neurite growth of stem cells and early neurons; (ii) factors acting retrogradely from the striatum, which are responsible for intrastriatal sprouting and navigation of newly arrived axons as well as life-long maintenance of the dopaminergic nigrostriatal connection; (iii) factors coming into play when the system is toxically impaired; (iv) factors directly acting on dopaminergic neurons; and (v) factors provided by cytokinestimulated astroglia, Microglia and neurons affecting dopaminergic neurons anterogradely. This article reviews actions of growth factors on dopaminergic neurons in vitro and in vivo, with a focus on members of the transforming growth factor (TGF)-beta superfamily. TGF-beta s may be particularly relevant to dopaminergic neurons, since they are expressed in the nigrostriatal system from early embryonic stages to adulthood and are significantly up-regulated in response to lesions

116. Yoshida T, Tanaka M, Sotomatsu A, Hirai S (1995) Activated Microglia cause superoxide-mediated release of iron from ferritin. Neurosci.Lett. 190:21-24
     Abstract: Ferritin contains the greatest part of the iron found in the brain, and the release of iron stores from ferritin has an essential role in iron-dependent lipid peroxidation. We examined the effect of cultured Microglia on iron mobilization from ferritin. Microglia stimulated by phorbol myristate acetate caused the release of iron from ferritin, which was detected by monitoring iron-ferrozine complex formation. This iron mobilization was mediated by Microglial superoxide production, as evidenced by the significant inhibitory effect of superoxide dismutase. The role of superoxide was also supported by the close correspondence of cumulative Microglial superoxide production, as demonstrated by the MCLA (Cypridina luciferin analogue)-dependent chemiluminescence assay, to the time course of iron release from ferritin. Iron release induced by activated Microglia may be partly responsible for the oxidative damage that is thought to occur in Parkinson's disease and other neurodegenerative disorders

117. Kuiper MA, Visser JJ, Bergmans PL, Scheltens P, Wolters EC (1994) Decreased cerebrospinal fluid nitrate levels in Parkinson's disease, Alzheimer's disease and multiple system atrophy patients. J.Neurol.Sci. 121:46-49
     Abstract: Nitric oxide (NO) is a recently discovered endogenous mediator of vasodilatation, neurotransmission, and macrophage cytotoxicity. NO is thought to have a function in memory and in long-term potentiation. At high concentrations NO is neurotoxic and may play a role in neurodegeneration. NO is formed from L-arginine by the enzyme NO synthase (NOS), for which tetrahydrobiopterin (BH4) is a necessary co-factor. Alzheimer's disease (AD) and, to a lesser degree, Parkinson's disease (PD) are thought to be associated with increased Microglial activity, suggesting that NO production may be increased. Alternatively, in circumstances of reduced levels of intracellular L-arginine or BH4, NO production is diminished and neurotoxic oxygen radicals may be produced. Since BH4 is decreased in AD and PD brains, these diseases may be associated with decreased NO production. We investigated these two alternatives by measuring the NO degradation products nitrite and nitrate in cerebrospinal fluid (CSF) of PD (n = 103), AD (n = 13), and multiple system atrophy (MSA; n = 14) patients and controls (n = 20). We found for all patient groups, compared with controls, significantly decreased levels of nitrate, but not nitrite. This finding seems to indicate a decreased NO production of the central nervous system (CNS) in these neurodegenerative disorders

118. Morris CM, Edwardson JA (1994) Iron histochemistry of the substantia nigra in Parkinson's disease. Neurodegeneration. 3:277-282
     Abstract: Raised tissue iron levels in the substantia nigra in Parkinson's disease (PD) suggests that altered iron homeostasis may underly the disorder. We have therefore investigated the distribution of non-haem iron in the normal and PD substantia nigra, using a sensitive histochemical procedure, to assess the pathogenic potential of this metal. In control cases non-haem iron staining was highest in the substantia nigra zona reticulata (SNr) and associated with the neuropil, oligodendrocytes, astrocytes and non-pigmented neurones. The substantia nigra zona compacta (SNc) showed lower non-haem iron staining than the SNr, with generalized impregnation of the neuropil and occasional non-haem iron-positive oligodendrocytes and astrocytes. The pigmented dopaminergic neurones were unstained, often present in areas of neuropil with low iron reactivity. In PD the SNc showed increased iron staining of the neuropil with many iron-positive Microglial cells associated with extracellular melanin. The remaining dopaminergic neurones were unstained, though many of the non-pigmented neurones of the SNr were iron-positive

119. Yamada T, Horisberger MA, Kawaguchi N, Moroo I, Toyoda T (1994) Immunohistochemistry using antibodies to alpha-interferon and its induced protein, MxA, in Alzheimer's and Parkinson's disease brain tissues. Neurosci.Lett. 181:61-64
     Abstract: The localization of alpha-interferon (alpha-IFN) and its induced protein, MxA, was examined in human brain tissues from neurologically normal, Alzheimer's disease (AD) and Parkinson's disease (PD) cases. In all cases, a few neurons in the superficial cortical layers and Microglial cells in the white matter were stained with the antibody to alpha-IFN. In AD brains, white matter Microglia were intensely labeled for alpha-IFN and reactive Microglia, such as those on senile plaques, were strongly positive for MxA protein. In PD, Lewy bodies in the substantia nigra were positive for MxA, but there was no staining for alpha-IFN in that region. These results suggest that increased expression of alpha-IFN in the white matter Microglia and appearance of MxA protein in reactive Microglia contribute to Alzheimer pathology. The staining of some Lewy bodies for MxA may be indicative of a viral infection or other unknown factor

120. Youdim MB, Lavie L (1994) Selective MAO-A and B inhibitors, radical scavengers and nitric oxide synthase inhibitors in Parkinson's disease. Life Sci. 55:2077-2082
     Abstract: In the absence of identification of either an endogenously or an exogenously derived dopaminergic neurotoxin, the most valid hypothesis currently envisaged for etiopathology of Parkinson's disease (PD) is selective oxidative stress (OS) in substantia nigra (SN). Although OS is not proven, a significant body of evidence from studies on animal and Parkinsonian brain neurochemistry supports it. This hypothesis is based on excessive formation of reactive oxygen species (O2 and OH.) and demise of systems involved with scavenging or preventing the formation of such radicals from H2O2, generated as a consequence of dopamine oxidation (autoxidation and deamination). Since MAO (monoamine oxidase A and B are the major H2O2 generating enzymes in the SN much attention has been paid to their selective inhibitors as symptomatic and neuroprotective agents in PD. Attention should also be given to radical scavengers (e.g. iron chelators, lipid peroxidative inhibitors and Vitamin E derivatives) as therapeutic neuroprotective agents in PD. This is considered valid since a significant elevation of iron is known to occur selectively in SN zone compacta and within the remaining melanized dopamine neurons of Parkinsonian brains. Although all the mechanism of iron induced oxygen free radical formation is not fully known there is no doubt that it participates with H2O2 (Fenton chemistry) to generate cytotoxic hydroxyl radical (OH.) and induce tissue OS and neurodegeneration in 6-hydroxydopamine model of PD. The dramatic proliferation of reactive amoeboid macrophages and Microglia seen in SN of PD brains together with OS is highly compatible with an inflammatory process, similar to what has been observed in Alzheimer's disease and multiple sclerosis brains. This has led us to examine the ability of reactive macrophages to produce oxygen free radicals in response to nitric oxide (NO) production. The latter radical has been implicated in the excitotoxicity of glutaminergic neurons innervating the striatum and SN. Indeed we have now observed that in reactive macrophages NO acts as a signal transducer of O2 production which can synergize with dopamine oxidation

121. Youdim MB, Lavie L, Riederer P (1994) Oxygen free radicals and neurodegeneration in Parkinson's disease: a role for nitric oxide. Ann.N.Y.Acad.Sci. 738:64-68

122. Van Gool D, De Strooper B, Van Leuven F, Triau E, Dom R (1993) alpha 2-Macroglobulin expression in neuritic-type plaques in patients with Alzheimer's disease. Neurobiol.Aging 14:233-237
     Abstract: Because it has been suggested that alpha 2M could be involved in the generation of amyloid peptide, attention was given to a possible association of alpha 2M expression and amyloid accumulation in the brain. Therefore, we investigated the presence of the proteinase inhibitor alpha 2-macroglobulin (alpha 2M) in the cerebra of 4 patients with Alzheimer's Disease (AD). One case of a patient with Down's syndrome, 2 cases of patients with Dementia of the Lewy Body type (DLB), 1 case of an aged, clinically nondemented person who displayed many amyloid plaques, and 3 normal aged control brains were also studied. The results obtained by immunocytochemistry with monoclonal antibodies directed against two different epitopes of human alpha 2M showed an association of alpha 2M, only with neuritic-type plaques in patients with AD. No alpha 2M immunoreactivity was found in either preamyloid-type plaques or burned out-type plaques in AD, DLB, or aged nondemented controls. The results do not support a direct role of this proteinase inhibitor in the formation of amyloid. Because alpha 2M is observed to be associated with reactive Microglia in the outer border of the neuritic plaques, the data suggest that alpha 2M could be a marker for an inflammatory cellular process in these neuritic plaques

123. Youdim MB, Riederer P (1993) The role of iron in senescence of dopaminergic neurons in Parkinson's disease. J.Neural Transm.Suppl 40:57-67
     Abstract: In Parkinson's disease (PD) an elevation of iron with staging of the disease has been observed in the substantia nigra (SN), especially the zona compacta (ZC). The iron is found to be present in glia, active Microglia, macrophages, oligodendrocytes, outside the degenerated dopamine neurons and as a mild halo around Lewy bodies and within melanized dopamine neurons of SNZC. Although in control brains iron is absent in melanized dopamine neurons, in PD it is bound to neuromelanin in a fashion similar to the interaction of iron with synthetic dopamine-melanin. The iron in SNZC is thought to induce oxidative stress and thus be associated with the reported decreases of glutathione peroxidase activity, reduced glutathione (GSH), mitochondrial Complex I activity, calcium binding protein and increase of basal lipid peroxidation. An animal (rat) model of PD has been described in which intranigral iron injection induces a relatively specific lesioning of dopamine neurons resulting in behavioural and biochemical Parkinsonism in rats. Support for the neurotoxicity of iron liberated from an endogenous source has come from the 6-hydroxydopamine model of PD. This neurotoxin is thought to owe its toxicity to the liberation of iron from ferritin, which in turn alters the homeostasis of mitochondrial Ca2+ with the subsequent depletion of tissue GSH, resulting in oxidative stress. Pretreatment of rats with intraventricular injection of a relatively selective prototype iron chelator, desferrioxamine (desferal), attenuates the 6-hydroxydopamine lesion of nigrostriatal dopamine. Thus iron can fulfill the role of a neurotoxin. However it remains to be established whether its role in PD is primary or secondary to some other neurotoxic event

124. Kida E, Barcikowska M, Niemczewska M (1992) Immunohistochemical study of a case with progressive supranuclear palsy without ophthalmoplegia. Acta Neuropathol.(Berl) 83:328-332
     Abstract: A case of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome; PSP) with Parkinsonism and absence of gaze palsy or mental changes is reported. Neuropathological examination, apart from typical changes, showed, lack of midbrain tegmentum demyelination, marked loss of Purkinje cells and presence of hyalin-like bodies in individual neurons of the substantia nigra. Immunostaining against tau-1 protein revealed the prevalence of a diffuse reaction in locus coeruleus neurons; reflecting either different ability of these cells to accumulate straight filaments, or a various time sequence of neurofibrillary tangles formation. Ferritin immunohistochemistry demonstrated widespread Microglial cell proliferation, confirming further the generalized character of CNS pathology in PSP

125. Yamada T, McGeer PL, McGeer EG (1992) Some immunohistochemical features of argyrophilic grain dementia with normal cortical choline acetyltransferase levels but extensive subcortical pathology and markedly reduced dopamine. J.Geriatr.Psychiatry Neurol. 5:3-13
     Abstract: Detailed immunohistochemical and biochemical studies are reported on two cases of progressive dementia showing no Alzheimer-type pathology but extensive argyrophilic grains as described previously by Braak and Braak. These cases had no specific clinical features, and the pathology of these brains showed subcortical gliosis (proliferation of astrocytes and Microglia) without significant neuronal losses. Interesting novel immunohistochemical findings were the profuse appearance of complement-activated oligodendrocytes and oligodendroglial microtubular masses. Their appearance seems to indicate oligodendroglial reactions to widespread damage of myelinated axons. Cortical levels of choline acetyltransferase were normal, but striatal levels of dopamine and its metabolites were markedly reduced. This disease may be consistent with the criteria for progressive subcortical gliosis

126. Jedrzejewska A, Dymecki J (1990) Intrastriatal grafts of adrenal medulla in hemiParkinsonian rats--ultrastructural study. Acta Neurobiol.Exp.(Wars.) 50:391-396
     Abstract: The aim of the study was to investigate the ultrastructure of the right striatum after intrastriatal adrenal medulla grafts in Wistar rats with a 6-OHDA unilateral lesion of the compact part of the right substantia nigra (SN). 12 adult rats were investigated. Two rats were intact, 2 received a sham SN-lesion. Ungerstedt's rotational test confirmed a significant lateral SN-lesion in all the animals. Two weeks after the SN lesion small samples of the adrenal medulla of 2-month old Wistar rats were prepared (0.5 mm3) and implanted stereotaxically into the middle-paraventricular region of the right striatum. The animals were perfused with 2.5% glutaraldehyd according to the following patern: 2--after 1 week of survival, 2--after 3 weeks, 2--after 6 weeks, and 2--after 3 months. 10 samples of ca 1 mm3 were taken from 3 regions of the right striatum (1) the region of the graft, (2) the region in the neighbourhood of the graft, (3) tissue at a long distance from the transplant. Macroscopic observation showed granulomatous-like tissue at the place of the implantation of the graft after 1 week of survival. After 3 weeks and later only the evacuated cavity was observed instead of the graft. A routine electron microscopic procedure was used to expose the material in a JEM 100 B electron microscope. The study of the ultrastructure indicated many leucocytes and Microglia cells in the region of the graft as well as features of destruction of the adrenal medulla cells in the rats perfused 1 and 3 weeks after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

127. Jellinger K, Paulus W, Grundke-Iqbal I, Riederer P, Youdim MB (1990) Brain iron and ferritin in Parkinson's and Alzheimer's diseases. J.Neural Transm.Park Dis.Dement.Sect. 2:327-340
     Abstract: Semiquantitative histological evaluation of brain iron and ferritin in Parkinson's (PD) and Alzheimer's disease (DAT) have been performed in paraffin sections of brain regions which included frontal cortex, hippocampus, basal ganglia and brain stem. The results indicate a significant selective increase of Fe3+ and ferritin in substantia nigra zona compacta but not in zona reticulata of Parkinsonian brains, confirming the biochemical estimation of iron. No such changes were observed in the same regions of DAT brains. The increase of iron is evident in astrocytes, macrophages, reactive Microglia and non-pigmented neurons, and in damaged areas devoid of pigmented neurons. In substantia nigra of PD and PD/DAT, strong ferritin reactivity was also associated with proliferated Microglia. A faint iron staining was seen occasionally in peripheral halo of Lewy bodies. By contrast, in DAT and PD/DAT, strong ferritin immunoreactivity was observed in and around senile plaques and neurofibrillary tangles. The interrelationship between selective increase of iron and ferritin in PD requires further investigation, because both changes could participate in the induction of oxidative stress and neuronal death, due to their ability to promote formation of oxygen radicals

128. McGeer PL, Itagaki S, Akiyama H, McGeer EG (1988) Rate of cell death in Parkinsonism indicates active neuropathological process. Ann.Neurol. 24:574-576
     Abstract: It has been hypothesized that idiopathic Parkinsonism might be due to age-related attrition of dopamine neurons occurring long after an initial acute episode. We present evidence against this hypothesis, based on our finding of at least six times as many HLA-DR-positive Microglia phagocytosing dopamine neurons in Parkinsonian brains as in control brains. This difference indicates an active pathological process

129. McGeer PL, Itagaki S, Boyes BE, McGeer EG (1988) Reactive Microglia are positive for HLA-DR in the substantia nigra of Parkinson's and Alzheimer's disease brains. Neurology 38:1285-1291
     Abstract: We detected large numbers of HLA-DR-positive reactive Microglia (macrophages), along with Lewy bodies and free melanin, in the substantia nigra of all cases studied with Parkinson's disease (5) and Parkinsonism with dementia (PD) (5). We found similar, but less extensive, pathology in the substantia nigra of six of nine cases of dementia of the Alzheimer type (DAT) but in only one of 11 age-matched nonneurologic cases. All dementia cases with a premortem diagnosis of DAT or PD showed large numbers of HLA-DR-positive reactive Microglia and significant plaque and tangle counts in the hippocampus, as well as reduced cortical choline acetyltransferase activity. One of 11 nondemented controls showed mild evidence of similar cortical pathology. These data indicate that HLA-DR-positive reactive Microglia are a sensitive index of neuropathologic activity. They suggest a frequent coexistence of DAT- and Parkinson-type pathology in elderly patients

130. McGeer PL, Itagaki S, McGeer EG (1988) Expression of the histocompatibility glycoprotein HLA-DR in neurological disease. Acta Neuropathol.(Berl) 76:550-557
     Abstract: Reactive Microglia or macrophages expressing the histocompatibility glycoprotein HLA-DR were detected in many neurological diseases including Alzheimer's, Parkinson's, Pick's and Huntington's diseases, Parkinsonism-dementia of Guam, amyotrophic lateral sclerosis, Shy-Drager syndrome, multiple sclerosis and AIDS encephalopathy. Reactive astrocytes, also present in these conditions, were established as a population distinct from the HLA-DR positive Microglia by double immunostaining for glial fibrillary acidic protein and HLA-DR. A distinctive pattern of HLA-DR positive cells was seen in each disease entity. Areas known to contain pathology always stained positively, and, in several cases, reactive Microglia appeared in areas that would otherwise not have been suspected of being involved in the pathological process. HLA-DR staining, which outlines the surface membranes of positive cells, was so strong that lesioned areas could frequently be identified in sections with the naked eye. In adjacent sections stained with H&E or sections destained of HLA-DR and then restained with H&E, gliosis was often hard to identify except on close microscopic inspection. The results suggest that HLA-DR staining may be a valuable addition to standard neuropathological methods and might be useful in investigating diseases where pathology has not yet been identified